Compounds containing hydrido-tricyano-borate anions

ABSTRACT

The present invention relates to compounds containing hydrido-tricyano-borate anions, their preparation and their use, in particular as part of electrolyte formulations for electrochemical or optoelectronic devices.

The present invention relates to compounds containinghydrido-tricyano-borate anions, their preparation and their use, inparticular as part of electrolyte formulations for electrochemical oroptoelectronic devices.

The salts according to the invention can on the one hand be used for thesynthesis of ionic liquids, on the other hand the salts can be employedper se as ionic liquid.

Ionic liquids or liquid salts are ionic species which consist of anorganic cation and a generally inorganic anion. They do not contain anyneutral molecules and usually have melting points below 373 K.

The area of ionic liquids is currently the subject of intensive researchsince the potential applications are multifarious. Review articles onionic liquids are, for example, R. Sheldon “Catalytic reactions in ionicliquids”, Chem. Commun., 2001, 2399-2407; M. J. Earle, K. R. Seddon“Ionic liquids. Green solvent for the future”, Pure Appl. Chem., 72(2000), 1391-1398; P. Wasserscheid, W. Keim “Ionische Flüssigkeiten—neueLosungen für die Übergangsmetallkatalyse” [Ionic Liquids—Novel Solutionsfor Transition-Metal Catalysis], Angew. Chem., 112 (2000), 3926-3945; T.Welton “Room temperature ionic liquids. Solvents for synthesis andcatalysis”, Chem. Rev., 92 (1999), 2071-2083 or R. Hagiwara, Ya. Ito“Room temperature ionic liquids of alkylimidazolium cations andfluoroanions”, J. Fluorine Chem., 105 (2000), 221-227.

The properties of ionic liquids, for example melting point, thermal andelectrochemical stability, viscosity, are strongly influenced by thenature of the anion.

E. Bernhardt et al, Z. Anorg. Allg. Chem. 2000, 626, 560, E. Bernhardtet al, Chem. Eur. J. 2001, 7, 4696 and E. Bernhardt et al, Z. Anorg.Allg. Chem. 2003, 629,1229 disclose the novel chemically andelectrochemically stable borate anions [B(CN)₄]⁻, [F_(x)B(CN)_(4-x)]⁻,where x=1 to 3, and [B(CF₃)₄]⁻.

EP 1205480 A1 describes tetrakisfluoroalkylborate salts and the usethereof as conductive salts or ionic liquids.

Compounds with dihydrido-dicyano-borate anions with organic cations suchas N,N-dimethyl-N-butyl-hydrazinium, N,N-dimethyl-N-allyl-hydrazinium,3-allyl-1-methylimidazolium, N-butylpyridinium, N-allylpyridinium,N-butyl-N-methyl-pyrrolidinium, N-allyl-N-methylpyrrolidinium,1-butyl-3-methyltriazolium or 1-allyl-3-methyltriazolium cations areknown from Zhang Y. and Shreeve J. M., Angew. Chem. 2011, vol. 123, p.965-967. The above mentioned organic salts are synthesized via anionexchange-reaction with Ag[BH₂(CN)₂].

But, silver salts are expensive materials. They are light sensitive,thermally not very stable and are not useful starting materials forindustrial scale production of various salts, in particular the saltshaving organic cations and thus forming ionic liquids.

The object of the present invention was to provide alternative compoundswhich are novel, thermally and electrochemically stable which can beused for the synthesis of ionic liquids or as ionic liquids or asconductive salts, and which are in particular useful for the synthesisof ionic liquids or as ionic liquids or organic salts for application inelectrochemical or optoelectronic devices. The object of the presentinvention was furthermore to provide a method for the preparation of thealternative salts, especially the compounds of formula I, as describedbelow, which can be produced in economical way on industrial scale.

The object is achieved by the salts of the formula I according to theinvention with hydrido-tricyano-borate anions and the described methodsfor their preparation.

The invention therefore relates to compounds of formula I[Kt]^(z+) z[BH(CN)₃]⁻  Iin which [Kt]^(z+) denotes an inorganic or organic cation and z is 1, 2,3 or 4, where sodium hydrido-tricyano-borate, potassiumhydrido-tricyano-borate, silver hydrido-tricyano-borate and[(Phenyl)₃P—N═N—P(Phenyl)₃]hydrido-tricyano-borate are excluded.

The term tricyano-hydridoborate is used within the description equallyto tricyanomonohydridoborate, hydrido-tricyanoborate ormonohydridotricyanoborate.

CN 1772728A describes a process for the preparation ofN-phenylhydroxylamine derivatives through reduction of nitobenzenes inwhich the reducing agent is described as being sodium borohydride,potassium borohydride, sodium hydrido-tricyano-borate, potassiumhydrido-tricyano-borate, sodium hydrogen selenide or selenium potassiumhydride. The synthesis of the sodium hydrido-tricyano-borate orpotassium hydrido-tricyano-borate is not mentioned within this citation.

B. Györi et al, Journal of Organometallic Chemistry, 255, 1983, 17-28describes the isomerisation of sodium triisocyanohydroborate (adductwith 0.5 mol of dioxane) to sodium hydrido-tricyano-borate in boilingn-dibutyl ether and a preparation of silver hydrido-tricyano-boratethrough reaction of sodium hydrido-tricyanoborate with an aqueoussolution of silver nitrate.

H. Yao et al, Inorg. Chem. 2005, 44, 6256-6264 describes the synthesisof silver triisocyanohydroborate (Ag[HB(NC)₃]) through reaction ofMe₂S*BHBr₂ in Me₂S with AgCN in Me₂S. The abbreviation Me means in thiscitation methyl. The crude material was reacted in a metathesis reactionwith PPNCl forming PPN[HB(NC)₃]which is then isomerised toPPN[HB(CN)₃]in boiling n-butyl ether.

The cation [Kt]^(z+) may be inorganic, in particular a metal cation, H⁺or NO⁺. The metal cation may comprise metals from groups 1 to 12 of thePeriodic Table. Preferred metal cations are metal cations, such as Li⁺,Na⁺, K⁺, Rb⁺, Cs⁺, or Mg²⁺, Cu⁺, Cu²⁺, Zn²⁺, Ca²⁺, Y⁺³, Yb⁺³, La⁺³,Sc⁺³, Ce⁺³, Nd⁺³, Tb⁺³, Sm⁺³ or complex (ligands containing) metalcations which include rare-earths, transitions or noble metals likerhodium, ruthenium, iridium, palladium, platinum, osmium, cobalt,nickel, iron, chromium, molybdenum, tungsten, vanadium, titanium,zirconium, hafnium, thorium, uranium, gold, where sodiumhydrido-tricyano-borate, potassium hydrido-tricyano-borate or silverhydrido-tricyano-borate is excluded from the scope of the inventedcompounds but still included for the described methods for thepreparations. The alkali metal is preferably lithium which is preferablyused as conducting salt and/or component of electrolytes for applicationin batteries, capacitors, sensors or for electrochemical processes, andsodium or potassium which is preferably used for the synthesis ofcompounds of formula I as described above and below in which the cation[Kt]^(z+) is a cation other than the used sodium or the used potassium,especially preferably for compounds of formula I in which the cation[Kt]^(z+) is an organic cation.

If [Kt]^(z+) is an organic cation, the organic cation is preferablyselected from the group comprising iodonium, tritylium, sulfonium,oxonium, ammonium, phosphonium, uronium, thiouronium, guanidiniumcations or heterocyclic cations.

Examples of organic cations are also polyammonium ions having a degreeof charging of 4 which means z denotes 4.

Preferred compounds of formula I are compounds, in which

-   Kt^(z+) denotes an inorganic cation selected from the group of H⁺,    NO⁺, Li⁺, Mg²⁺, Cu⁺, Cu²⁺, Zn²⁺, Ca²⁺, Y⁺³, Yb⁺³, La⁺³, Sc⁺³, Ce⁺³,    Nd⁺³, Tb⁺³, Sm⁺³ or complex (ligands containing) metal cations which    include rare-earths, transitions or noble metals like rhodium,    ruthenium, iridium, palladium, platinum, osmium, cobalt, nickel,    iron, chromium, molybdenum, tungsten, vanadium, titanium, zirconium,    hafnium, thorium, uranium, gold,-   or an organic cation selected from the group of-   tritylium cation, in which the phenyl groups may be substituted by    straight-chain or branched alkyl groups having 1 to 20 C atoms,    straight-chain or branched alkenyl having 2 to 20 C atoms and one or    more double bonds or straight-chain or branched alkynyl having 2 to    20 C atoms and one or more triple bonds,-   an oxonium cation of formula (1) or a sulfonium cation of formula    (2)    [(R^(o) )₃O]⁺  (1)    [(R^(o) )₃S]⁺  (2),    -   where R^(o) each independently of one another denotes a        straight-chain or branched alkyl group having 1-8 C atoms,        non-substituted phenyl or phenyl which is substituted by R¹*,        OR′, N(R)₂, CN or halogen and in case of sulfonium cations of        formula (2) additionally denotes each independently (R′″)₂N and        R′ is independently of each other H, non-fluorinated, partially        fluorinated or perfluorinated straight-chain or branched C₁- to        C₁₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or        substituted phenyl, R1* is independently of each other        non-fluorinated, partially fluorinated or perfluorinated        straight-chain or branched C₁- to C₁₈-alkyl, saturated C₃- to        C₇-cycloalkyl, non-substituted or substituted phenyl and R′″ is        independently of each other straight-chain or branched C₁ to C₆        alkyl;-   an ammonium cation, which conforms to the formula (3)    [NR₄]⁺  (3),    -   where    -   R in each case, independently of one another, denotes    -   H, OR′, N(R′)₂, with the proviso that a maximum of one R in        formula (3) is OR′ or N(R′)₂,    -   straight-chain or branched alkyl having 1-20 C atoms,    -   straight-chain or branched alkenyl having 2-20 C atoms and one        or more double bonds,    -   straight-chain or branched alkynyl having 2-20 C atoms and one        or more triple bonds,    -   saturated, partially or fully unsaturated cycloalkyl having 3-7        C atoms, which may be substituted by straight-chain or branched        alkyl groups having 1-6 C atoms,    -   where one or two R may be fully substituted by halogens, in        particular —F and/or —Cl, and one or more of the substituents R        may be partially substituted by halogens, in particular —F        and/or —Cl, and/or by —OH, —OR′, —CN, —N(R′)₂, —C(O)OH,        —C(O)OR′, —C(O)R′, —C(O)N(R′)₂, —SO₂N(R′)₂, —C(O)X, —SO₂OH,        —SO₂X, —NO₂, —SR′, —S(O)R′, —SO₂R′ and where one or two        non-adjacent carbon atoms in R which are not in the α-position        may be replaced by atoms and/or atom groups selected from the        group —O—, —S—, —S(O)—, —SO₂—, —SO₂O—, —C(O)—, —C(O)O—,        —N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—, —OP(O)R′O—,        —P(O)(N(R′)₂)NR′—, —P(R′)₂═N— or —P(O)R′— where R′ each        independently is H, non-fluorinated, partially fluorinated or        perfluorinated straight-chain or branched C₁- to C₁₈-alkyl,        saturated C₃- to C₇-cycloalkyl, non-substituted or substituted        phenyl and X each independently is halogen;-   a phosphonium cation, which conforms to the formula (4)    [P(R²)₄]⁺  (4),    -   where    -   R² in each case, independently of one another, denotes    -   H, OR′ or N(R′)₂,    -   straight-chain or branched alkyl having 1-20 C atoms,    -   straight-chain or branched alkenyl having 2-20 C atoms and one        or more double bonds,    -   straight-chain or branched alkynyl having 2-20 C atoms and one        or more triple bonds,    -   saturated, partially or fully unsaturated cycloalkyl having 3-7        C atoms, which may be substituted by straight-chain or branched        alkyl groups having 1-6 C atoms,    -   where one or two R² may be fully substituted by halogens, in        particular —F and/or —Cl, and one or more of the substituents R²        may be partially substituted by halogens, in particular —F        and/or —Cl, and/or by —OH, —OR′, —CN, —N(R′)₂, —C(O)OH,        —C(O)OR′, —C(O)R′, —C(O)N(R′)₂, —SO₂N(R′)₂, —C(O)X, —SO₂OH,        —SO₂X, —NO₂, —SR′, —S(O)R′, —SO₂R′ and where one or two        non-adjacent carbon atoms in R² which are not in the α-position        may be replaced by atoms and/or atom groups selected from the        group —O—, —S—, —S(O)—, —SO₂—, —SO₂O—, —C(O)—, —C(O)O—,        —N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—, —OP(O)R′O—,        —P(O)(N(R′)₂)NR′—, —P(R′)₂═N— or —P(O)R′— where R′ each        independently is H, non-fluorinated, partially fluorinated or        perfluorinated straight-chain or branched C₁- to C₁₈-alkyl,        saturated C₃- to C₇-cycloalkyl, non-substituted or substituted        phenyl and X each independently is halogen;-   a uronium cation, which conforms to the formula (5)    [C(NR³R⁴)(OR⁵)(NR⁶R⁷)]⁺  (5),    -   where    -   R³ to R⁷ each, independently of one another, denote    -   H, where H is excluded for R⁵,    -   straight-chain or branched alkyl having 1 to 20 C atoms,    -   straight-chain or branched alkenyl having 2-20 C atoms and one        or more double bonds,    -   straight-chain or branched alkynyl having 2-20 C atoms and one        or more triple bonds,    -   saturated, partially or fully unsaturated cycloalkyl having 3-7        C atoms, which may be substituted by straight-chain or branched        alkyl groups having 1-6 C atoms,    -   where one or two of the substituents R³ to R⁷ may be fully        substituted by halogens, in particular —F and/or —Cl, and one or        more of the substituents R³ to R⁷ may be partially substituted        by halogens, in particular —F and/or —Cl, and/or by —OH, —OR′,        —N(R′)₂, —CN, —C(O)OH, —C(O)OR′, —C(O)R′, —C(O)N(R′)₂,        —SO₂N(R′)₂, —C(O)X, —SO₂OH, —SO₂X, —SR′, —S(O)R′, —SO₂R′, —NO₂        and where one or two non-adjacent carbon atoms in R³ to R⁷ which        are not in the α-position may be replaced by atoms and/or atom        groups selected from the group —O—, —S—, —S(O)—, —SO₂—, —SO₂O—,        —C(O)—, —C(O)O—, —N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—,        —OP(O)R′O—, —P(O)(N(R′)₂)NR′—, —P(R′)₂═N— or —P(O)R′— where R′        each independently is H, non-fluorinated, partially fluorinated        or perfluorinated straight-chain or branched C₁- to C₁₈-alkyl,        saturated C₃- to C₇-cycloalkyl, non-substituted or substituted        phenyl and X each independently is halogen;-   a thiouronium cation, which conforms to the formula (6)    [C(NR³R⁴)(SR⁵)(NR⁶R⁷)]⁺  (6),    -   where    -   R³ to R⁷ each, independently of one another, denote    -   H, where H is excluded for R⁵,    -   straight-chain or branched alkyl having 1 to 20 C atoms,    -   straight-chain or branched alkenyl having 2-20 C atoms and one        or more double bonds,    -   straight-chain or branched alkynyl having 2-20 C atoms and one        or more triple bonds,    -   saturated, partially or fully unsaturated cycloalkyl having 3-7        C atoms, which may be substituted by straight-chain or branched        alkyl groups having 1-6 C atoms,    -   where one or two of the substituents R³ to R⁷ may be fully        substituted by halogens, in particular —F and/or —Cl, and one or        more of the substituents R³ to R⁷ may be partially substituted        by halogens, in particular —F and/or —Cl, and/or by —OH, —OR′,        —N(R′)₂, —CN, —C(O)OH, —C(O)OR′, —C(O)R′, —C(O)N(R′)₂,        —SO₂N(R′)₂, —C(O)X, —SO₂OH, —SO₂X, —SR′, —S(O)R′, —SO₂R′, —NO₂        and where one or two non-adjacent carbon atoms in R³ to R⁷ which        are not in the α-position may be replaced by atoms and/or atom        groups selected from the group —O—, —S—, —S(O)—, —SO₂—, —SO₂O—,        —C(O)—, —C(O)O—, —N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—,        —OP(O)R′O—, —P(O)(N(R′)₂)NR′—, —P(R′)₂═N— or —P(O)R′— where R′        each independently is H, non-fluorinated, partially fluorinated        or perfluorinated straight-chain or branched C₁- to C₁₈-alkyl,        saturated C₃- to C₇-cycloalkyl, non-substituted or substituted        phenyl and X each independently is halogen;    -   a guanidinium cation, which conforms to the formula (7)        [C(NR⁸R⁹)(NR¹⁰R¹¹)(NR¹²R¹³)]⁺  (7),    -   where    -   R⁸ to R¹³ each, independently of one another, denote    -   H, —CN, N(R′)₂, —OR′,    -   straight-chain or branched alkyl having 1 to 20 C atoms,    -   straight-chain or branched alkenyl having 2-20 C atoms and one        or more double bonds,    -   straight-chain or branched alkynyl having 2-20 C atoms and one        or more triple bonds,    -   saturated, partially or fully unsaturated cycloalkyl having 3-7        C atoms, which may be substituted by straight-chain or branched        alkyl groups having 1-6 C atoms,    -   where one or two of the substituents R⁸ to R¹³ may be fully        substituted by halogens, in particular —F and/or —Cl, and one or        more of the substituents R⁸ to R¹³ may be partially substituted        by halogens, in particular —F and/or —Cl, and/or by —OH, —OR′,        —N(R′)₂, —CN, —C(O)OH, —C(O)OR′, —C(O)R′, —C(O)N(R′)₂,        —SO₂N(R′)₂, —C(O)X, —SO₂OH, —SO₂X, —SR′, —S(O)R′, —SO₂R′, —NO₂        and where one or two non-adjacent carbon atoms in R⁸ to R¹³        which are not in the α-position may be replaced by atoms and/or        atom groups selected from the group —O—, —S—, —S(O)—, —SO₂—,        —SO₂O—, —C(O)—, —C(O)O—, —N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—,        —SO₂NR′—, —OP(O)R′O—, —P(O)(N(R′)₂)NR′—, —P(R′)₂═N— or —P(O)R′—,        where R′ each independently is H, non-fluorinated, partially        fluorinated or perfluorinated straight-chain or branched C₁- to        C₁₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or        substituted phenyl and X each independently is halogen;-   a heterocyclic cation which conforms to the formula (8)    [HetN]^(z+)  (8)    -   where    -   HetN^(z+) denotes a heterocyclic cation selected from the group

-   -   where the substituents    -   R¹′ to R⁴′ each, independently of one another, denote H,    -   straight-chain or branched alkyl having 1-20 C atoms,    -   straight-chain or branched alkenyl having 2-20 C atoms and one        or more double bonds,    -   straight-chain or branched alkynyl having 2-20 C atoms and one        or more triple bonds,    -   saturated, partially or fully unsaturated cycloalkyl having 3-7        C atoms, which may be substituted by straight-chain or branched        alkyl groups having 1-6 C atoms,    -   saturated, partially or fully unsaturated heteroaryl,        heteroaryl-C₁-C₆-alkyl or aryl-C₁-C₆-alkyl and    -   R^(2′) denote additionally F, Cl, Br, I, —CN, —OR′, —N(R′)₂,        —P(O)(R′)₂, —P(O)(OR′)₂, —P(O)(N(R′)₂)₂, —C(O)R′, —C(O)OR′,        —C(O)X, —C(O)N(R′)₂, —SO₂N(R′)₂, —SO₂OH, —SO₂X, —SR′, —S(O)R′,        —SO₂R′ and/or NO₂, with the proviso that R¹′, R³′, R⁴′ are in        this case independently of each other H and/or a straight-chain        or branched alkyl having 1-20 C atoms, straight-chain or        branched alkenyl having 2-20 C atoms and one or more double        bonds,    -   where the substituents R^(1′), R^(2′), R^(3′) and/or R^(4′)        together may also form a ring system,    -   where one to three substituents R^(1′) to R^(4′) may be fully        substituted by halogens, in particular —F and/or —Cl, and one or        more substituents R^(1′) to R^(4′) may be partially substituted        by halogens, in particular —F and/or —Cl, and/or by —OH, —OR′,        N(R′)₂, —CN, —C(O)OH, —C(O)OR′, —C(O)R′, —C(O)N(R′)₂,        —SO₂N(R′)₂, —C(O)X, —SO₂OH, —SO₂X, —SR′, —S(O)R′, —SO₂R′, —NO₂,        but where R^(1′) and R^(4′) cannot simultaneously be fully        substituted by halogens and where, in the substituents R^(1′) to        R^(4′), one or two non-adjacent carbon atoms which are not        bonded to the heteroatom may be replaced by atoms and/or atom        groups selected from the —O—, —S—, —S(O)—, —SO₂—, —SO₂O—,        —C(O)—, —C(O)O—, —N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—,        —OP(O)R′O—, —P(O)(N(R′)₂)NR′—, —P(R′)₂═N— or —P(O)R′—,    -   where R′ each independently is H, non-fluorinated, partially        fluorinated or perfluorinated straight-chain or branched C₁- to        C₁₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or        substituted phenyl and X each independently is halogen or

-   a iodonium cation which conforms to the formula (9)

-   -   where    -   the aryl group Ar denotes each independently of each other aryl        with 6 to 30 C atoms which is non-substituted or substituted        with at least a straight-chain or branched alkyl group having 1        to 20 C atoms, a straight-chain or branched alkenyl group having        2 to 20 C atoms and one or more double bonds, a straight-chain        or branched alkynyl group having 2 to 20 C atoms and one or more        triple bonds, R¹*, NO₂, SR′, N(R′)₂, CN and/or halogen and where        R′ each independently is H, non-fluorinated, partially        fluorinated or perfluorinated straight-chain or branched C₁- to        C₁₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or        substituted phenyl and    -   where R¹* each independently is non-fluorinated, partially        fluorinated or perfluorinated straight-chain or branched C₁- to        C₁₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted or        substituted phenyl

-   and halogen is F, Cl, Br or I.

Halogen is preferably F, Cl or Br, particularly preferably F or Cl.

The compounds of formula I having organic cations are possessing lowviscosity. Some of the viscosities are even lower compared with thecorresponding tetracyanoborates having the same organic cation. Forexample, 1-ethyl-3-methyl-imidazolium tetracyanoborate (emim TCB) hasthe dynamic viscosity of 22 mPas (at 20° C.) and the corresponding1-ethyl-3-methyl-imidazolium hydrido-tricyano-borate has a viscosity of12.2 mPas (at 20° C.). In addition, the thermal stability of suchcompounds is higher compared to compounds with organic cations withdihydrido-dicyano-borate anions or difluorodicyanoborate anions. Forexample, emim difluoro-dicyanoborate has a thermal stability up to 160°C., emim dihydrido-dicyano-borate shows a thermal stability up to 230°C. and emim hydrido-tricyanoborate has a thermal stability up to 277° C.which is comparable to the stability of emim TCB. The positive influenceof the replacement of one cyano-group with hydrogen on the viscosity ofcompounds of formula I compared to the compounds with tetracyanoborateanions is unexpected. In comparison to electron-withdrawing groups likefluor, perfluoroalkyl or cyano groups which are able to effectivelydelocalise the negative charge of borate anions, hydrogen practicallydoes not participate in the stabilization of borate-anion. Theintroduction of one hydrogen atom to Boron should increase thecoordination ability of the tricyano-hydrido borate anion, causingincrease in the viscosity of ionic liquids with this anion. But theexperimental results are totally opposite from the theoretical point ofview.

Not being bound by that theory, it seams that the introduction of onehydrogen atom to Boron breaks the symmetry of tetracyano-borate anionresulting in strong decreasing of ionic liquids viscosity.

Another advantage of compounds of formula I is that they can be preparedfrom commercially available starting materials via a simple reactionprotocol.

R^(o) of the)[(R^(o))₃O]⁺ cation (formula (1)) is preferablystraight-chain alkyl having 1-8 C atoms, preferably having 1-4 C atoms,in particular methyl or ethyl, very particularly preferably ethyl.

R^(o) of the)[(R^(o))₃S]⁺ cation (formula (2)) is preferablystraight-chain alkyl having 1-8 C atoms, preferably having 1-4 C atoms,in particular methyl or ethyl, very particularly preferably ethyl. Thisdefinition is preferably for the technical application as component ofan electrolyte.

At least one substitutent R⁰ within the sulfonium cations of formula (2)is preferably phenyl or substituted phenyl in case the sulfonium cationis chosen together with the inventive anion as cationic polymerizationinitiator, photo-polymerization initiator or photo-acid generator.Particularly preferably all substituents R⁰ in formula (2) are for thisapplication each independently phenyl and/or phenyl substituted with SR′where R′ has a meaning as described before.

Preferred cations of formula (2) for this application aretriphenylsulfonium, diphenyltolylsulfonium, diphenylethylsulfonium,diphenyl-2,2,2-trifluorethyl sulfonium,diphenyl-2-ethoxy-ethylsulfonium, diphenyl-2-chlorethylsulfonium,diphenyl-3-brompropylsulfonium, diphenyl-3-chlorpropylsulfonium,diphenyl-3-cyanopropylsulfonium, diphenylallylsulfonium,diphenyl-4-pentenylsulfonium, diphenylpropargylsulfonium,diphenylbenzylsulfonium, diphenyl(p-cyanobenzyl)sulfonium,diphenyl(p-methylbenzyl)sulfonium,diphenyl(p-phenylthiobenzyl)sulfonium,diphenyl(3,3-dicyano-2-phenyl-2-propenyl)sulfonium,diphenyl(p-methylphenacyl)sulfonium,diphenyl(ethylcarboxy)methylsulfonium, diphenyl(n-octyl)sulfonium,diphenyl(n-octadecyl)sulfonium, diphenyl(w-carboxytridecyl)sulfonium,diphenyl(3-oxypropyl)sulfonium, diphenyl(w-carboxydodecyl)sulfonium,dihexyl-phenylsulfonium, ditolylphenylsulfonium, tritolylsulfonium, m-or p-(tert-butyl)phenyl-diphenylsulfonium, m- orp-methoxyphenyl-diphenylsulfonium, m- or p-CN-phenyl-diphenylsulfonium,m- or p-C₆H₁₃S-phenyl-diphenylsulfonium, m- orp-C₆H₅S-phenyl-diphenylsulfonium, Tri(p-methoxyphenyl)sulfonium,tri[4-(4-acetyl-phenylsulfanyl)phenyl]sulfonium,tri(4-tert.-butylphenyl)sulfonium.

For the purposes of the present invention, fully unsaturated cycloalkylsubstituents are also taken to mean aromatic substituents.

In accordance with the invention, suitable substituents R and R² to R¹³of the compounds of the formulae (3) to (7) are preferably: H, C₁- toC₂₀-, in particular C₁- to C₁₋₄-alkyl groups, and saturated orunsaturated, i.e. also aromatic, C₃- to C₇-cycloalkyl groups, which maybe substituted by C₁- to C₆-alkyl groups, in particular phenyl which maybe substituted by C₁- to C₆-alkyl groups.

The substituents R and R² in the compounds of the formula (3) or (4) maybe identical or different. The substituents R and R² are preferablydifferent.

The substituents R and R² are particularly preferably methyl, ethyl,isopropyl, propyl, butyl, sec-butyl, pentyl, hexyl, octyl, decyl ortetradecyl.

Up to four substituents of the guanidinium cation[C(NR⁸R⁹)(NR¹⁰R¹¹)(NR¹²R¹³)]⁺ may also be bonded in pairs in such a waythat mono-, bi- or polycyclic cations are formed.

Without restricting generality, examples of such guanidinium cationsare:

where the substituents R⁸ to R¹⁰ and R¹³ can have a meaning orparticularly preferred meaning indicated above.

If desired, the carbocycles or heterocycles of the guanidinium cationsindicated above may also be substituted by straight-chain or branchedC₁- to C₆-alkyl, straight-chain or branched C₁- to C₆-alkenyl, —CN,—NO₂, F, Cl, Br, I, OH, straight-chain or branched C₁-C₆-alkoxy,—N(R′)₂, —SR′, —S(O)R′, —SO₂R′, —COOH, —C(O)OR′, —C(O)R′, —C(O)N(R′)₂,—SO₂N(R′)₂, —C(O)X, —SO₂X, —SO₃H, substituted or non-substituted phenylor a non-substituted or substituted heterocycle, where X and R′ have ameaning indicated above.

Up to four substituents of the uronium cation [C(NR³R⁴)(OR⁵)(NR⁶R⁷)]⁺ orthiouronium cation [C(NR³R⁴)(SR⁵)(NR⁶R⁷)]⁺ may also be bonded in pairsin such a way that mono-, bi- or polycyclic cations are formed.

Without restricting generality, examples of such cations are indicatedbelow, where Y═O or S:

where the substituents R³, R⁵ and R⁶ can have a meaning or particularlypreferred meaning indicated above.

If desired, the carbocycles or heterocycles of the cations indicatedabove may also be substituted by straight-chain or branched C₁- toC₆-alkyl, straight-chain or branched C₁- to C₆-alkenyl, —CN, —NO₂, F,Cl, Br, I, OH, straight-chain or branched C₁-C₆-alkoxy, —N(R′)₂, —SR′,—S(O)R′, —SO₂R′, —COOH, —C(O)OR′, —C(O)R′, —C(O)N(R′)₂, —SO₂N(R′)₂,—C(O)X, —SO₂X, —SO₃H, substituted or non-substituted phenyl or anon-substituted or substituted heterocycle, where X and R′ have ameaning indicated above.

The substituents R³ to R¹³ are each, independently of one another,preferably a straight-chain or branched alkyl group having 1 to 16 Catoms. The substituents R³ and R⁴, R⁶ and R⁷, R⁸ and R⁹, R¹⁰ and R¹¹ andR¹² and R¹³ in compounds of the formula (5) to (7) may be identical ordifferent. R³ to R¹³ are particularly preferably each, independently ofone another, methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl,sec-butyl, phenyl, hexyl or cyclohexyl, very particularly preferablymethyl, ethyl, n-propyl, iso-propyl, n-butyl or hexyl.

In accordance with the invention, suitable substituents R^(1′) to R^(4′)of compounds of the formula (8) are each, independently of one another,preferably,

-   H,-   straight-chain or branched alkyl having 1 to 20 C atoms, which    optionally may be fluorinated or perfluorinated,-   straight-chain or branched alkenyl having 2 to 20 C atoms and one or    more double bonds, which optionally may be fluorinated,-   straight-chain or branched alkynyl having 2 to 20 C atoms and one or    more triple bonds which optionally may be fluorinated or-   straight-chain or branched alkoxyalkyl having 2 to 8 C atoms, with    the assumption that R^(1′) and R^(4′) are not simultaneously be    perfluorinated.

The substituents R^(1′) and R^(4′) are each, independently of oneanother, particularly preferably straight-chain or branched alkyl having1 to 20 C atoms, which optionally may be fluorinated or perfluorinatedor straight-chain or branched alkoxyalkyl having 2 to 8 C atoms with theassumption that R^(1′) and R^(4′) are not perfluorinated at the sametime.

The substituents R^(1′) and R^(4′) are each, independently of oneanother, particularly preferably methyl, ethyl, allyl, iso-propyl,propyl, butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl,n-decyl, cyclohexyl, methoxyethyl, methoxymethyl, ethoxyethyl,ethoxymethyl, phenyl or benzyl. They are very particularly preferablymethyl, ethyl, propyl n-butyl or methoxyethyl. In pyrrolidinium,piperidinium or indolinium compounds, the two substituents R^(1′) andR^(4′) are preferably different.

In accordance with the invention, suitable substituents R^(2′) andR^(3′) of compounds of formula (8) are particularly preferably: H,straight-chain or branched C₁- to C₂₀-, in particular C₁- to C₁₋₂-alkylgroups, and saturated or unsaturated, i.e. also aromatic, C₃- toC₇-cycloalkyl groups, which may be substituted by straight-chain orbranched C₁- to C₆-alkyl groups, in particular phenyl.

The substituent R^(2′) or R^(3′) is in each case, independently of oneanother, in particular H, methyl, ethyl, iso-propyl, propyl, butyl,sec-butyl, tert-butyl, cyclohexyl, phenyl or benzyl. R^(2′) isparticularly preferably H, methyl, ethyl, iso-propyl, propyl, butyl orsec-butyl. R^(3′) is particularly preferably H. R^(2′) and R^(3′) arevery particularly preferably H.

A straight-chain or branched alkyl having 1-20 C atoms denotes an alkylgroup having 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,18, 19 or 20 C atoms, for example methyl, ethyl, iso-propyl, n-propyl,iso-butyl, n-butyl, tert-butyl, n-pentyl, 1-, 2- or 3-methylbutyl, 1,1-,1,2- or 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, n-heptyl, n-octyl,ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl,n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl,n-nonadecyl or eicosyl, which optionally may be fluorinated orperfluorinated. The term “perfluorinated” means that all H atoms aresubstituted by F atoms in the given alkyl group. The term “fluorinated”means that at least one H atom of the given alkyl group is substitutedby an F atom.

A straight-chain or branched alkenyl having 2 to 20 C atoms, in which aplurality of double bonds may also be present, is, for example, allyl,2- or 3-butenyl, iso-butenyl, sec-butenyl, furthermore 4-pentenyl,iso-pentenyl, hexenyl, heptenyl, octenyl, —C₉H₁₇, —C₁₀H₁₉ to —C₂₀H₃₉,preferably allyl, 2- or 3-butenyl, iso-butenyl, sec-butenyl, furthermorepreferably 4-pentenyl, isopentenyl or hexenyl, which may be optionallypartially fluorinated.

A straight-chain or branched alkynyl having 2 to 20 C atoms, in which aplurality of triple bonds may also be present, is, for example, ethynyl,1- or 2-propynyl, 2- or 3-butynyl, furthermore 4-pentynyl, 3-pentynyl,hexynyl, heptynyl, octynyl, —C₉H₁₅, —C₁₀H₁₇ to —C₂₀H₃₇, preferablyethynyl, 1- or 2-propynyl, 2- or 3-butynyl, 4-pentynyl, 3-pentynyl orhexynyl, which may be optionally partially fluorinated.

A straight-chain or branched alkoxyalkyl having 2 to 12 C atoms is, forexample, methoxymethyl, 1-methoxyethyl, 1-methoxypropyl,1-methoxy-2-methyl-ethyl, 2-methoxy-propyl, 2-methoxy-2-methyl-propyl,1-methoxybutyl, 1-methoxy-2,2-dimethyl-ethyl, 1-methoxy-pentyl,1-methoxyhexyl, 1-methoxy-heptyl, ethoxymethyl, 1-ethoxyethyl,1-ethoxypropyl, 1-ethoxy-2-methyl-ethyl, 1-ethoxybutyl,1-ethoxy-2,2-dimethyl-ethyl, 1-ethoxypentyl, 1-ethoxyhexyl,1-ethoxyheptyl, propoxymethyl, 1-propoxyethyl, 1-propoxypropyl,1-propoxy-2-methyl-ethyl, 1-propoxybutyl, 1-propoxy-2,2-dimethyl-ethyl,1-propoxypentyl, butoxymethyl, 1-butoxyethyl, 1-butoxypropyl or1-butoxybutyl. Particularly preferred is methoxymethyl, 1-methoxyethyl,2-methoxy-propyl, 1-methoxypropyl, 2-methoxy-2-methyl-propyl or1-methoxybutyl.

Aryl with 6 to 30 C atoms denotes an aryl group with 6 to 30 C atoms andis an aromatic group with aromatic delocalized electrons, optionallysubstituted one or more times by R¹*, OR′, N(R′)₂, CN, NO₂ or halogen.An aryl group with 6 to 30 C atoms, preferably with 6 to 24 C atoms, isfor example 1-, 2-, 3-, 4-, 5- or 6-phenyl, 1-, 2-, 3-, 4-, 6-, 7- or8-naphthyl, 1-, 2-, 3-, 4-, 6-, 7- or 8-phenanthrenyl, 1-, 2-, 3-, 4-,5-, 6-, 7-, 8-, 9- or 10-anthracenyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-,9-, 10-, 11- or 12-tetracenyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-,11- or 12-benzo[a]anthracenyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-,11-, 12-, 13- or 15-pentacenyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-,11- or 12-chrysenyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-pyrenyl,1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 11- or 12-benzo[a]pyrenyl, 1-,2-, 3-, 4-, 5-, 6-, 7- or 8-azulenyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-or 10-fluoranthenyl, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 11- or12-perylenyl, 1-, 2-, 3-, 4-, 5-, 6- or 7-indenyl or 1-, 2-, 3-, 4-, 5-,6-, 7-, 8- or 9-fluorenyl which is preferably non-substituted orsubstituted by R¹*, OR, N(R)₂, CN or halogen. Preferably, aryl denotes1-, 2-, 3-, 4-, 5- or 6-phenyl, 1-, 2-, 3-, 4-, 6-, 7- or 8-naphthylwhich is non-substituted or substituted by R¹*, OR′, N(R′)₂, CN orhalogen. R¹* and R′ have a meaning as described above.

Aryl-C₁-C₆-alkyl denotes, for example, benzyl, phenylethyl,phenylpropyl, phenylbutyl, phenylpentyl or phenylhexyl, where both thephenyl ring and also the alkylene chain may be partially or fullysubstituted, as described above, by halogens, in particular —F and/or—Cl, or partially by —OH, —OR′, —N(R′)₂, —CN, —C(O)OH, —C(O)N(R′)₂,—SO₂N(R′)₂, —C(O)X, —C(O)OR′, —C(O)R′, —SO₂OH, —SO₂X, —SR′, —S(O)R′,—SO₂R′, —NO₂ and R′ and X have a meaning as described above.

Non-substituted saturated or partially or fully unsaturated cycloalkylgroups having 3-7 C atoms are therefore cyclopropyl, cyclobutyl,cyclopentyl, cyclo-hexyl, cycloheptyl, cyclopentenyl,cyclopenta-1,3-dienyl, cyclohexenyl, cyclohexa-1,3-dienyl,cyclohexa-1,4-dienyl, phenyl, cycloheptenyl, cyclohepta-1,3-dienyl,cyclohepta-1,4-dienyl or cyclohepta-1,5-dienyl, each of which may besubstituted by straight-chain or branched C₁- to C₆-alkyl groups, wherethe cycloalkyl group or the cycloalkyl group substituted bystraight-chain or branched C₁- to C₆-alkyl groups may in turn also besubstituted by halogen atoms, such as F, Cl, Br or I, in particular F orCl, or by —OH, —OR′, —N(R′)₂, —CN, —C(O)OH, —C(O)N(R′)₂, —SO₂N(R′)₂,—C(O)X, —C(O)OR′, —C(O)R′, —SO₂OH, —SO₂X, —SR′, —S(O)R′, —SO₂R′, —NO₂and R′ and X have a meaning as described above.

In the substituents R, R² to R¹³ or R^(1′) to R^(4′), one or twonon-adjacent carbon atoms which are not bonded in the α-position to theheteroatom may also be replaced by atoms and/or atom groups selectedfrom the group O, —S—, —S(O)—, —SO₂—, —SO₂O—, —C(O)—, —C(O)O—, —N⁺R′₂—,—P(O)R′O—, —C(O)NR′—, —SO₂NR′—, —OP(O)R′O—, —P(O)(NR′₂)NR′—, —PR′₂═N— or—P(O)R′—, where R′

is non-fluorinated, partially fluorinated or perfluorinated C₁- toC₁₈-alkyl, saturated C₃- to C₇-cycloalkyl, non-substituted orsubstituted phenyl.

Without restricting generality, examples of substituents R, R² to R¹³and R^(1′) to R^(4′) modified in this way are:

—OCH₃, —OCH(CH₃)₂, —CH₂OCH₃, —CH₂—CH₂—O—CH₃, —C₂H₄OCH(CH₃)₂, —C₂H₄C₂H₅,—C₂H₄SCH(CH₃)₂, —S(O)CH₃, —SO₂CH₃, —SO₂C₆H₅, —SO₂C₃H₇, —SO₂CH(CH₃)₂,—SO₂CH₂CF₃, —CH₂SO₂CH₃, —O—C₄H₈—O—C₄H₉, —CF₃, —C₂F₅, —C₃F₇, —C₄F₉,—C(CF₃)₃, —CF₂SO₂CF₃, —C₂F₄N(C₂F₅)C₂F₅, —CHF₂, —CH₂CF₃, —C₂F₂H₃, —C₃H₆,—CH₂C₃F₇, —C(CFH₂)₃, —CH₂C(O)OH, —CH₂C₆H₅, —C(O)C₆H₅ or P(O)(C₂H₅)₂.

In R′ or R¹*, C₃- to C₇-cycloalkyl is, for example, cyclopropyl,cyclobutyl, cyclo-pentyl, cyclohexyl or cycloheptyl.

In R′ or R¹*, substituted phenyl denotes phenyl which is substituted bystraight-chain or branched C₁- to C₆-alkyl, straight-chain or branchedC₁- to C₆-alkenyl, —CN, —NO₂, F, Cl, Br, I, —OH, straight-chain orbranched-C₁-C₆-alkoxy, N(R″)₂, —COOH, —C(O)OR″, —C(O)R″, —SO₂X′, —SR″,—S(O)R″, —SO₂R″, SO₂N(R″)₂ or SO₃H, where X′ denotes F, Cl or Br and R″denotes a non-fluorinated, partially fluorinated or perfluorinatedstraight-chain or branched C₁- to C₆-alkyl or C₃- to C₇-cycloalkyl asdefined for R′, for example o-, m- or p-methylphenyl, o-, m- orp-ethylphenyl, o-, m- or p-propylphenyl, o-, m- or p-isopropylphenyl,o-, m- or p-tert-butylphenyl, o-, m- or p-nitrophenyl, o-, m- orp-hydroxyphenyl, o-, m- or p-methoxyphenyl, o-, m- or p-ethoxyphenyl,o-, m-, p-(trifluoromethyl)phenyl, o-, m-, p-(trifluoromethoxy)phenyl,o-, m-, p-(trifluoromethylsulfonyl)phenyl, o-, m- or p-fluorophenyl, o-,m- or p-chlorophenyl, o-, m- or p-bromophenyl, o-, m- or p-iodophenyl,further preferably 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-dimethyl-phenyl,2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-dihydroxyphenyl, 2,3-, 2,4-, 2,5-,2,6-, 3,4- or 3,5-difluorophenyl, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or3,5-dichlorophenyl, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-dibromophenyl,2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-di-methoxyphenyl,5-fluoro-2-methylphenyl, 3,4,5-trimethoxyphenyl or2,4,5-trimethylphenyl.

In R^(1′) to R^(4′), heteroaryl is taken to mean a saturated orunsaturated mono- or bicyclic heterocyclic group having 5 to 13 ringmembers, in which 1, 2 or 3 N and/or 1 or 2 S or O atoms may be presentand the heterocyclic radical may be mono- or poly-substituted bystraight-chain or branched C₁- to C₆-alkyl, straight-chain or branchedC₁- to C₆-alkenyl, —CN, —NO₂, F, Cl, Br, I, —OH, —N(R″)₂, straight-chainor branched C₁-C₆-alkoxy, —COOH, —C(O)OR″, —C(O)R″, —SO₂X′, —SO₂N(R″)₂,—SR″, —S(O)R″, —SO₂R″ or SO₃H, where X′ and R″ have a meaning indicatedabove.

The heterocyclic group is preferably substituted or non-substituted 2-or 3-furyl, 2- or 3-thienyl, 1-, 2- or 3-pyrrolyl, 1-, 2-, 4- or5-imidazolyl, 3-, 4- or 5-pyrazolyl, 2-, 4- or 5-oxazolyl, 3-, 4- or5-isoxazolyl, 2-, 4- or 5-thiazolyl, 3-, 4- or 5-isothiazolyl, 2-, 3- or4-pyridyl, 2-, 4-, 5- or 6-pyrimidinyl, furthermore preferably1,2,3-triazol-1-, -4- or -5-yl, 1,2,4-triazol-1-, -4- or -5-yl, 1- or5-tetrazolyl, 1,2,3-oxadiazol-4- or -5-yl, 1,2,4-oxadiazol-3- or -5-yl,1,3,4-thiadiazol-2- or -5-yl, 1,2,4-thiadiazol-3- or -5-yl,1,2,3-thiadiazol-4- or -5-yl, 2-, 3-, 4-, 5- or 6-2H-thiopyranyl, 2-, 3-or 4-4H-thiopyranyl, 3- or 4-pyridazinyl, pyrazinyl, 2-, 3-, 4-, 5-, 6-or 7-benzofuryl, 2-, 3-, 4-, 5-, 6- or 7-benzothienyl, 1-, 2-, 3-, 4-,5-, 6- or 7-1H-indolyl, 1-, 2-, 4- or 5-benzimidazolyl, 1-, 3-, 4-, 5-,6- or 7-benzopyrazolyl, 2-, 4-, 5-, 6- or 7-benzoxazolyl, 3-, 4-, 5-, 6-or 7-benzisoxazolyl, 2-, 4-, 5-, 6- or 7-benzothiazolyl, 2-, 4-, 5-, 6-or 7-benzisothiazolyl, 4-, 5-, 6- or 7-benz-2,1,3-oxadiazolyl, 1-, 2-,3-, 4-, 5-, 6-, 7- or 8-quinolinyl, 1-, 3-, 4-, 5-, 6-, 7- or8-isoquinolinyl, 1-, 2-, 3-, 4- or 9-carbazolyl, 1-, 2-, 3-, 4-, 5-, 6-,7-, 8- or 9-acridinyl, 3-, 4-, 5-, 6-, 7- or 8-cinnolinyl, 2-, 4-, 5-,6-, 7- or 8-quinazolinyl or 1-, 2- or 3-pyrrolidinyl.

Heteroaryl-C₁-C₆-alkyl is, analogously to aryl-C₁-C₆-alkyl, taken tomean, for example, pyridinylmethyl, pyridinylethyl, pyridinylpropyl,pyridinylbutyl, pyri-dinylpentyl, pyridinylhexyl, where the heterocyclesdescribed above may furthermore be linked to the alkylene chain in thisway.

HetN^(z+) is preferably

where the substituents R^(1′) to R^(4′) each, independently of oneanother, have a meaning described above.

HetN^(z+) is particularly preferably

where the substituents R^(1′) to R^(4′) each, independently of oneanother, have a meaning described above.

HetN^(z+) is very particularly preferably

where the substituents R^(1′) to R^(4′) each, independently of oneanother, have a meaning described above. Preferred meanings of R^(1′) toR^(4′) within imidazolium or pyrrolidinium cations are defined in thefollowing terms:

Preferred 1,1-dialkylpyrrolidinium cations are, for example,1,1-dimethyl-pyrrolidinium, 1-methyl-1-ethylpyrrolidinium,1-methyl-1-propylpyrrolidinium, 1-methyl-1-butylpyrrolidinium,1-methyl-1-pentylpyrrolidinium, 1-methyl-1-hexylpyrrolidinium,1-methyl-1-heptylpyrrolidinium, 1-methyl-1-octylpyrrolidinium,1-methyl-1-nonylpyrrolidinium, 1-methyl-1-decylpyrrolidinium,1,1-diethylpyrrolidinium, 1-ethyl-1-propylpyrrolidinium,1-ethyl-1-butylpyrrolidinium, 1-ethyl-1-pentylpyrrolidinium,1-ethyl-1-hexylpyrrolidinium, 1-ethyl-1-heptylpyrrolidinium,1-ethyl-1-octylpyrrolidinium, 1-ethyl-1-nonylpyrrolidinium,1-ethyl-1-decylpyrrolidinium, 1,1-dipropylpyrrolidinium,1-propyl-1-methyl-pyrrolidinium, 1-propyl-1-butylpyrrolidinium,1-propyl-1-pentylpyrrolidinium, 1-propyl-1-hexylpyrrolidinium,1-propyl-1-heptylpyrrolidinium, 1-propyl-1-octylpyrrolidinium,1-propyl-1-nonylpyrrolidinium, 1-propyl-1-decyl-pyrrolidinium,1,1-dibutylpyrrolidinium, 1-butyl-1-methylpyrrolidinium,1-butyl-1-pentylpyrrolidinium, 1-butyl-1-hexylpyrrolidinium,1-butyl-1-heptyl-pyrrolidinium, 1-butyl-1-octylpyrrolidinium,1-butyl-1-nonylpyrrolidinium, 1-butyl-1-decylpyrrolidinium,1,1-dipentylpyrrolidinium, 1-pentyl-1-hexyl-pyrrolidinium,1-pentyl-1-heptylpyrrolidinium, 1-pentyl-1-octylpyrrolidinium,1-pentyl-1-nonylpyrrolidinium, 1-pentyl-1-decylpyrrolidinium,1,1-dihexyl-pyrrolidinium, 1-hexyl-1-heptylpyrrolidinium,1-hexyl-1-octylpyrrolidinium, 1-hexyl-1-nonylpyrrolidinium,1-hexyl-1-decylpyrrolidinium, 1,1-dihexyl-pyrrolidinium,1-hexyl-1-heptylpyrrolidinium, 1-hexyl-1-octylpyrrolidinium,1-hexyl-1-nonylpyrrolidinium, 1-hexyl-1-decylpyrrolidinium,1,1-diheptyl-pyrrolidinium, 1-heptyl-1-octylpyrrolidinium,1-heptyl-1-nonylpyrrolidinium, 1-heptyl-1-decylpyrrolidinium,1,1-dioctylpyrrolidinium, 1-octyl-1-nonyl-pyrrolidinium,1-octyl-1-decylpyrrolidinium, 1,1-dinonylpyrrolidinium,1-nonyl-1-decylpyrrolidinium or 1,1-didecylpyrrolidinium. Veryparticular preference is given to 1-butyl-1-methylpyrrolidinium or1-propyl-1-methylpyrrolidinium.

Preferred 1-alkyl-1-alkoxyalkylpyrrolidinium cations are, for example,1-methoxymethyl-1-methyl-pyrrolidinium,1-methoxymethyl-1-ethyl-pyrrolidinium,1-(2-methoxyethyl)-1-methylpyrrolidinium,1-(2-methoxyethyl)-1-ethylpyrrolidinium,1-(2-methoxyethyl)-1-propylpyrrolidinium,1-(2-methoxyethyl)-1-butylpyrrolidinium,1-(2-ethoxyethyl)-1-methylpyrrolidinium,1-ethoxymethyl-1-methylpyrrolidinium,1-ethoxymethyl-1-ethyl-pyrrolidinium. Very particular preference isgiven to 1-(2-methoxyethyl)-1-methylpyrrolidinium.

Preferred 1,3-dialkylimidazolium cations are, for example,1-ethyl-3-methyl-imidazolium, 1-methyl-3-propylimidazolium,1,2,3-trimethylimidazolium, 1-ethyl-2,3-dimethylimidazolium,1-propyl-2,3-dimethylimidazolium, 1-butyl-2,3-dimethylimidazolium,1-butyl-3-methylimidazolium, 1-methyl-3-pentylimidazolium,1-ethyl-3-propylimidazolium, 1-butyl-3-ethylimidazolium,1-ethyl-3-pentylimidazolium, 1-butyl-3-propylimidazolium,1,3-dimethyl-imidazolium, 1,3-diethylimidazolium,1,3-dipropylimidazolium, 1,3-dibutylimidazolium,1,3-dipentylimidazolium, 1,3-dihexylimidazolium,1,3-di-heptylimidazolium, 1,3-dioctylimidazolium,1,3-dinonylimidazolium, 1,3-didecylimidazolium,1-hexyl-3-methylimidazolium, 1-heptyl-3-methylimidazolium,1-methyl-3-octylimidazolium, 1-methyl-3-nonylimidazolium,1-decyl-3-methylimidazolium, 1-ethyl-3-hexylimidazolium,1-ethyl-3-heptylimidazolium, 1-ethyl-3-octylimidazolium,1-ethyl-3-nonylimidazolium or 1-decyl-3-ethyl-imidazolium. Particularlypreferred cations are 1-ethyl-3-methylimidazolium,1-butyl-3-methylimidazolium or 1-methyl-3-propylimidazolium.

Preferred 1-alkoxyalkyl-3-alkylimidazolium cations are, for example1-methoxymethyl-3-methylimidazolium, 1-methoxymethyl-3-ethylimidazolium,1-methoxymethyl-3-butylimidazolium,1-(2-methoxyethyl)-3-methylimidazolium,1-(2-methoxyethyl)-3-ethylimidazolium,1-(2-methoxyethyl)-3-propyl-imidazolium,1-(2-methoxyethyl)-3-butylimidazolium,1-(2-ethoxyethyl)-3-methylimidazolium,1-ethoxymethyl-3-methylimidazolium.

Preferred 1-alkenyl-3-alkylimidazolium cations are, for example1-allyl-3-methyl-imidazolium or 1-allyl-2,3-dimethylimidazolium.

Preferred cations of formula (9) are diphenyliodonium, ditolyliodonium,phenyltolyliodonium, tolyl-(4-sec.-butylphenyl)iodonium,di(p-tert-butylphenyl)iodonium, p-methoxyphenyl-phenyliodonium,di(p-methoxyphenyl)iodonium, m- or p-CN-phenyl-phenyliodonium, m- orp-(C₆H₅S)-phenyl-phenyliodonium.

The organic cations of the compounds of formula I according to theinvention are preferably sulfonium, ammonium, phosphonium cations offormula (2), (3) and (4) or heterocyclic cations of formula (8),particularly preferably sulfonium cations of formula (2) or heterocycliccations of formula (8) as described above, especially for theapplication as electrolyte component.

The organic cations of the compounds of formula I according to theinvention are very particularly preferably heterocyclic cations offormula (8) in which HetN^(z+) is as defined above, where thesubstituents R^(1′) to R^(4′) each, independently of one another, have ameaning described above for the application as electrolyte component.The organic cation of the compound of formula I is very particularlypreferably imidazolium, where the substituents R^(1′) to R^(4′) each,independently of one another, have a meaning described above or has oneof the particularly preferred meanings of 1,3-dialkylimidazolium,1-alkenyl-3-alkylimidazolium or 1-alkoxyalkyl-3-alkylimidazolium asdescribed above.

Particularly suitable organic cations of the formula I are for thisapplication 1-butyl-1-methylpyrrolidinium, 1-ethyl-3-methylimidazolium,1-ethyl-2,3-dimethylimidazolium, 1-(2-methoxyethyl)-3-methylimidazolium,1-butyl-3-methylimidazolium, tributyl-methylammonium,tetra-n-butylammonium, tributyl-methylphosphonium,tetra-phenylphosphonium, diethyl-methylsulfonium,S-ethyl-N,N,N′,N′-tetramethylisothiouronium,1-allyl-3-methylimidazolium, 1-allyl-2,3-dimethylimidazolium,1-cyanomethyl-3-methylimidazolium, 1-methyl-3-propinylimidazlium,1,1-dimethylpyrrolidinium or trimethylsulfonium.

It goes without saying to the person skilled in the art thatsubstituents, such as, for example, C, H, N, O, Cl, F, in the compoundsaccording to the invention may be replaced by the correspondingisotopes.

Compounds of formula I in which [Kt]^(Z+) is Li⁺ can be preferably usedas conductive salts in primary batteries, secondary batteries,capacitors, supercapacitors or electrochemical cells, optionally also incombination with further conductive salts and/or additives, asconstituent of a polymer electrolyte or phase-transfer medium.

Compounds of formula I in which [Kt]^(Z+) is Na⁺ or K⁺ can be preferablyused as starting materials for compounds of formula I in which [Kt]^(z+)is an organic cation or another inorganic cation than sodium orpotassium.

Compounds of formula I in which [Kt]^(z+) corresponds to formula (2),(5), (6), (9), tritylium, pyrylium, 1-benzopyrylium or 2-benzopyryliumas described above or preferably described above are preferably used ascationic polymerization initiator, photo-polymerization initiator orphoto-acid generator. Particularly preferred organic cations to be usedfor this technical application corresponds to triarylsulfonium- ordiaryliodonium cations in which aryl is defined as described above forthe cations of formula (9).

Very particularly preferred organic cations to be used for thistechnical application as cationic polymerization initiator,photo-polymerization initiator or photo-acid generator aretriphenylsulfonium, tritolylsulfonium,p-(tert-butyl)phenyl-diphenylsulfonium,p-methoxyphenyl-diphenylsulfonium, p-C₆H₁₃S-phenyl-diphenylsulfonium, m-or (p-C₆H₅S-phenyl)-diphenylsulfonium,tri[4-(4-acetyl-phenylsulfanyl)phenyl]sulfonium,tri(4-tert.-butylphenyl)sulfonium, diphenyliodonium, ditolyliodonium,phenyltolyliodonium, di(p-tert-butylphenyl)iodonium, m- or(p-C₆H₅S-phenyl)-phenyliodonium or tolyl-(4-sec.-butylphenyl)iodonium.

In addition, the invention relates to a process for the preparation of acompound of formula I as described before in which [Kt]^(z+) is analkali metal cation and z denotes 1 which denotes a compound of formulaI-1 including sodium hydrido-tricyano-borate and potassiumhydrido-tricyano-borate,[Me]⁺[BH(CN)₃]⁻  I-1comprising in step 1 the reaction of a compound of formula II[Me¹]⁺[B(CN)₄]⁻  IIwith an alkali metal [Me],where [Me¹]⁺ in formula II denotes an alkali metal cation which isdifferent or equal to the alkali metal [Me] resulting in the formationof a compound of formula III{[Me]⁺}₂[B(CN)₃]²⁻  IIIin which [Me]⁺ denotes the alkali metal cation of the alkali metal andcomprising in step 2 the hydrolysis of the compound of formula IIIresulted from step 1.

Compounds of formula II are commercially available e.g. from Merck KGaA,Darmstadt or can be synthesized according to WO 2004/072089, especiallyas disclosed in examples 1 to 3.

Alkali metals are commercially available materials.

[Me]⁺ is preferably K⁺ or Na⁺, especially preferably K⁺. [Me] ispreferably lithium, sodium, potassium or their mixtures, especiallypreferably sodium.

The process for the preparation of compounds of the formula I in which[Kt]^(z+) is an alkali metal cation and z denotes 1 which denotes acompound of formula I-1 as described above is carried out in liquidammonia or in organic solvents which are inert to alkali metals, forexample tetrahydrofuran, dialkyl ethers or amide-based solvents. Ifreaction proceeds in organic solvent the application of some catalysts,for example benzophenone, can accelerate the process and improve theyield of compounds of formula III.

Useful amide solvents are N,N-dimethylformamide, N,N-dimethylacetamide,N-methylpyrrolidone or HMPT (hexamethylphosphortriamide).

Liquid ammonia is condensed at temperatures around −78° C. and thereaction mixture is warmed up to a temperature between −50° C. to −30°C. in the presence of an inert atmosphere, like nitrogen or argonfollowed by warming up to 10° C. to 30° C. and evaporation of ammonia.

The hydrolysis of step 2 is preferably carried out in water attemperatures between 15° C. and 30° C., preferably at room temperature,in the absence or in the presence of an inorganic base such as alkalimetal carbonates or acetates, or organic bases, preferablytrialkylamines.

It is preferable to purify the compounds of formula I-1 by extractionwith an organic solvent.

Useful organic solvents are for example, acetonitrile, dimethoxyethane,diglyme, tetrahydrofurane, or methyl-tert-butyl ether.

In addition, the invention relates to a special process for thepreparation of a compound of formula I as described above in which[Kt]^(Z+) is the cation of potassium and z denotes 1 which denotes acompound of formula I-2[K]⁺[BH(CN)₃]⁻  I-2comprising the reaction of a compound of formula IV[Me²]⁺[BH₄]⁻  IVin which [Me²]⁺ denotes an alkali metal cationwith {4KSCN+K₂[Zn(SCN)₄]} and purification from minor amounts of theoptional side product K[BH₂(CN)₂].

The reaction is carried out in a solid state reaction in inertatmosphere (nitrogen or argon) at temperatures between 100° C. to 220°C., preferably at 150° C. to 200° C., especially preferably at 185° C.

After cooling to room temperature, the mixture is dissolved in water andpurified according to known methods in the art such as extractionmethods.

The complex of rhodanid salts can be prepared from commerciallyavailable sodium or potassium rhodanid and zinc sulfate.

[Me²]⁺ is preferably K⁺ or Na⁺, especially preferably Na⁺. Sodium andpotassium tetrahydridoborate is commercially available.

In addition, the invention relates to a process for the preparation of acompound of formula I as described above in which [Kt]^(Z+) is an alkalimetal cation and z denotes 1 comprising the reaction of a compound offormula II[Me¹]⁺[B(CN)₄]⁻  IIwith a strong base, preferably an alkali metal hydroxide, an alkalimetal amide, a substituted amide or alkali metal alcoholate, where[Me¹]⁺ in formula II denotes an alkali metal cation which is differentor equal to the alkali metal cation of the alkali metal hydroxide,alkali metal amide or alkali metal alcoholate. The alkali metalhydroxide is especially preferably used as strong base in the reactionwith compounds of formula II.

The reaction is carried out without solvent or in the presence of anorganic solvent at a temperature between 20° C. and 200° C., preferablyat 50° C. to 200° C., preferably at 100° to 160° C.

Useful organic solvents are for example acetonitrile, dimethoxyethane,diglyme, tetrahydrofurane or methyl-tert-butyl-ether or amide solvents,like N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidoneor HMPT (hexamethylphosphortriamide).

The process for the preparation of compounds of formula I in which thecation is an organic cation or an inorganic cation other than analkalimetal cation is a metathesis reaction (salt-exchange reaction) inwhich the cation will be replaced as commonly known.

The invention therefore also relates to a process for the preparation ofa compound of formula I according to one or more of claims 1 to 3 inwhich [Kt]^(z+) is another cation than the used alkali metal cation inthe starting material and z is 1, 2, 3 or 4 including sodiumhydrido-tricyano-borate, potassium hydrido-tricyano-borate and silverhydrido-tricyano-borate in a salt-exchange reaction, characterized inthat an alkali metal salt of formula I-1[Me]⁺[BH(CN)₃]⁻  I-1in which [Me]⁺ is an alkali metal cation or H[BH(CN)₃] is reacted with acompound of formula VKtA  V,in which

Kt has a meaning of an organic cation or inorganic cation other than thealkali metal cation of the compound of formula I-1 or H⁺ and

A denotes F⁻, Cl⁻, Br⁻, I⁻, OH⁻, [HF₂]⁻, [CN]⁻, [SCN]⁻, [R₁COO]⁻,[R₁OC(O)O]⁻, [R₁SO₃]⁻, [R₂COO]⁻, [R₂SO₃]⁻, [R₁OSO₃]⁻, [PF₆]⁻, [BF₄]⁻,[HSO₄]¹⁻, [SO₄]²⁻, [NO₃]⁻, [(R₂)₂P(O)O]⁻, [R₂P(O)O₂]²⁻, [(R₁O₂P(O)O]⁻,[(R₁O)P(O)O₂]²⁻, [(R₁O)R₁P(O)O]⁻, tosylate, malonate which may besubstituted by straight-chain or branched alkyl groups having 1 to 4 Catoms, [HOCO₂]⁻ or [CO₃]²⁻, with the proviso that [SO₄]²⁻ and [CO₃]²⁻are used merely for the synthesis of compounds of formula I havinganother metal cation than the alkali metal cation of the compound offormula I-1,

in which R₁ is each independently of another a straight-chain orbranched alkyl group having 1 to 12 C atoms and

R₂ is each independently of one another a straight-chain or branchedperfluorinated alkyl group having 1 to 12 C atoms and whereelectroneutrality should be taken into consideration in the formula ofthe salt KtA.

R₂ is particularly preferred trifluoromethyl, pentafluoroethyl ornonafluorobutyl, very particularly preferred trifluoromethyl orpentafluoroethyl.

R₁ is particularly preferred methyl, ethyl, n-butyl, n-hexyl or n-octyl,very particularly preferred methyl or ethyl.

Compounds of formula I-1, as described above, are preferably used in themetathesis reaction as described above.

Substituted malonates are for example methyl malonate or ethyl malonate.

The compounds of formula V are in most cases commercially available orcan be synthesised by known processes. Known processes for thepreparation of compounds of formula V are described, for example, in P.Wasserscheid, T. Welton (Eds.), Ionic Liquids in Synthesis, SecondEdition, WILEY-VCH, Weinheim, 2008.

The anion in the formula V is preferably OH⁻, Cl⁻, Br⁻, I⁻, [HF₂]⁻,[CN]⁻, [SCN]⁻, [CH₃OC(O)O]⁻, [CH₃C(O)O]⁻, [CH₃SO₃]⁻, [CF₃C(O)O]⁻,[CF₃SO₃]⁻, [CH₃OSO₃]⁻, [SiF₆]²⁻, [PF₆]⁻, [BF₄]⁻, [HSO₄]¹⁻, [NO₃]⁻,[C₂H₅OSO₃]⁻, [(C₂F₅)₂P(O)O]⁻, [C₂F₅P(O)O₂]²⁻, tosylates, malonates or[SO₄]²⁻ and [CO₃]²⁻ with the proviso that [SO₄]²⁻ and [CO₃]⁻ are usedmerely for the synthesis of compounds of formula I having another metalcation than the alkali metal cation of the compound of formula I-1,particularly preferably OH⁻, Cl⁻, Br⁻, I⁻, [CH₃SO₃]⁻, [CH₃OSO₃]⁻,[PF₆]⁻, [CF₃COO]⁻, [CF₃SO₃]⁻, [(C₂F₅)₂P(O)O]⁻ or [CO₃]²⁻.

The anion in the formula V is very particularly preferably OH⁻, Cl⁻,Br⁻, [CH₃OSO₃]⁻, [CF₃SO₃]−, [CH₃SO₃]⁻ for the synthesis of compounds offormula I having an inorganic cation and the anion in the formula V isvery particularly preferably OH⁻, Cl⁻, Br⁻, [CH₃OSO₃]⁻, [PF₆]⁻,[CF₃SO₃]⁻, [CH₃SO₃]⁻ or [(C₂F₅)₂P(O)O]⁻ for the synthesis of compoundsof formula I having an organic cation.

Suitable organic salts for the preparation of the compounds of theformula I in which [Kt]^(z+) is an organic cation are salts with cationsof formula (1) to (8) or their preferred embodiments together withanions as defined as A described above or its preferred embodimentswhich means salts of cations of formulae (1) to (8) or their preferredembodiments and OH⁻, Cl⁻, Br⁻, [CH₃OSO₃]⁻, [PF₆]⁻, [CF₃SO₃]⁻, [CH₃SO₃]⁻or [(C₂F₅)₂P(O)O]⁻.

Suitable substance for the preparation of the compound of the formula Iin which [Kt]^(z+) is H⁺ are aqueous H[BF₄] and H[PF₆] or H[BF₄] andH[PF₆] in organic solvents, preferably in diethylether. Reaction ofK[BH(CN)₃] or Na[BH(CN)₃] with H[BF₄] or H[PF₆] results in the formationof H[BH(CN)₃] in solvated form and purely soluble potassium or sodiumhexafluorophosphate or tetrafluoroborate.

Suitable inorganic salts for the preparation of the compounds of theformula I in which [Kt]^(z+) is a metal cation e.g. from the groupsilver, magnesium, copper, zinc and calcium are, for example, Ag₂O,Ag₂CO₃, MgCO₃, CuO, ZnO, Zn[HCO₃]₂, CaCO₃ or Ca(OC(O)CH₃)₂. Useful saltsfor metathesis reaction to another alkali metal salt of formula I thanpotassium are e.g. LiBF₄.

The reaction is advantageously carried out in water in the case of thecompounds of formula I-1 or in organic solvent, where temperatures of10°-100° C., preferably 15°-60° C., particularly preferably roomtemperature, are suitable.

However, the reaction can alternatively also be carried out for thecompounds of formula I in organic solvents at temperatures between 10°and 100° C. Suitable solvents here are acetonitrile, dialkylethers,tetrahydrofurane, dioxane, dichloromethane, dimethoxyethane or analcohol, for example methanol, ethanol or iso-propanol.

The present invention furthermore relates to compounds of formula III{[Me]⁺}₂[B(CN)₃]²⁻  IIIin which [Me]⁺ denotes an alkali metal cation, which is preferably Li⁺,Na⁺ or K⁺.

The present invention furthermore relates to the corresponding processfor the preparation of a compound of formula III as described abovecomprising the reaction of a compound of formula II[Me¹]⁺[B(CN)₄]⁻  IIin which [Me¹]⁺ denotes an alkali metal cation with an alkali metal[Me¹] in which the alkali metal [Me¹] and the alkali metal cation [Me¹]⁺are the same or different.

The reaction above is carried out in liquid ammonia or in organicsolvents which are inert to alkali metals, for example tetrahydrofuran,dialkyl ethers or amide-based solvents. Liquid ammonia is condensed attemperatures around −78° C. and the reaction mixture is warmed up to atemperature between −50° C. to −30° C. in the presence of an inertatmosphere, like nitrogen or argon followed by warming up to 10° C. to30° C. and evaporation of ammonia.

The salts Na₂[B(CN)₃], Li₂[B(CN)₃] and K₂[B(CN)₃] are very moisturesensitive compounds, but they can be stored in the glove-box for a longtime. These salts are soluble in liquid ammonia, dimethylformamide,slightly soluble in acetonitrile and NH₂CH₂CH₂NH₂. They are insoluble intetrahydrofuran and diethylcarbonate.

The invention furthermore relates to the use of compounds of formula IIIas described above for the introduction of B(CN)₃-groups in chemicalsubstances via reaction with electrophiles.

The present invention furthermore relates to the use of the compounds offormula I as described above as media for chemical reactions, ascatalyst and/or as media in catalytical processes, as conducting salts,as components of electrolytes for the application in electrochemicalcells, as components of supporting electrolytes for electrochemicalprocesses, as surfactants, as phase-transfer catalysts, as trainer, asextractant; as antistatic additive, as plasticiser; asheat-transfer-medium, as modifier for membranes and textile materials;as lubricant, as additive to lubricant compositions or to anotherengineering fluids; as hydraulic fluid or as additive to hydraulicfluids.

Preferably, compounds of formula I having inorganic cations as describedabove are useful as catalyst, as conducting salts, as components ofelectrolytes for the application in electrochemical cells, as componentsof supporting electrolytes for electrochemical processes, assurfactants, as phase-transfer catalysts or as antistatic additive.

Preferably, compounds of formula I having organic cations as describedabove or H⁺ are useful as media for chemical reactions, as catalystand/or as media in catalytical processes, as conducting salts, ascomponents of electrolytes for the application in electrochemical cells,as components of supporting electrolytes for electrochemical processes,as surfactants, as phase-transfer catalysts, as trainer, as extractant;as antistatic additive, as plasticiser; as heat-transfer-medium, asmodifier for membranes and textile materials; as lubricant, as additiveto lubricant compositions or to another engineering fluids; as hydraulicfluid or as additive to hydraulic fluids.

In the case of the use of the said organic salts of formula I as mediain catalytical processes or as solvents, these are suitable in any typeof reaction known to the person skilled in the art, for example fortransition-metal- or enzyme-catalysed reactions, such as, for example,hydroformylation reactions, oligomerisation reactions, esterificationsor isomerisations, where the said list is not exhaustive.

On use as extractant, the organic salts of formula I can be employed toseparate off reaction products, but also to separate off impurities,depending on the solubility of the respective component in the ionicliquid. In addition, the ionic liquids may also serve as separationmedia in the separation of a plurality of components, for example in thedistillative separation of a plurality of components of a mixture.

Further possible applications are use as plasticiser in polymermaterials and as conductive salt or additive in various electrochemicalcells and applications, for example in galvanic cells, in capacitors orin fuel cells.

Further fields of applications of the organic salts of formula I,according to this invention are solvents for carbohydrate containingsolids in particular biopolymers and derivatives or degredation productsthereof. In addition, these new compounds can be applied as lubricants,working fluids for maschines, such as compressors, pumps or hydraulicdevices. A further field of application is the field of particle ornanomaterial synthesis where these ionic liquids can act as medium oradditive.

The compounds of formula I in which [Kt]^(z+) corresponds to formula(2), (5), (6), (9), tritylium, pyrylium, 1-benzopyrylium or2-benzopyrylium as described above or preferably described above arepreferably used as cationic polymerization initiator,photo-polymerization initiator or photo-acid generator.

A cationic polymerization initiator is able to start the polymerizationof at least one monomer, for example the polymerization of cationicpolymerizable compounds such as iso-butylene, styrene, vinylethers,lactones, lactames, cyclic ethers or epoxy-containing compounds.

The process of polymerization is started via radiation in case aphoto-polymerization initiator is used which means that the mixture ofphoto-initiator and at least one monomer is irradiated through energeticrays such as light, electrons or gamma rays. This kind ofphoto-polymerization normally leads especially to quickly crosslinkedend products. The compounds of formula I with cations of formula (2),(5), (6), (9), tritylium, pyrylium, 1-benzopyrylium or 2-benzopyryliumas described above are cationic photo-polymerization initiators.Particularly, compounds of formula I with cations of formula (2) and (9)are preferred.

Photo-polymerization initiators are often components of formulations oflacquers or resins which often need a curing in fractional amounts ofseconds. The curing may be inititated through light, laser, electrons orgamma rays, especially through UV-light.

Photo-polymerization is often used in various technical applications forexample for curing a coating film, forming a planographic printingplate, a resin letterpress printing plate and a printed circuit board,preparing a photoresist and a photomask, and making a black-and-white orcolor transfer sheet and a coloring sheet.

In case the compounds of formula I with cations of formula (2), (5),(6), (9), tritylium, pyrylium, 1-benzopyrylium or 2-benzopyrylium areirradiated with light, laser, electrons or gamma rays, they are able tobuild the corresponding Brønsted acid or Lewis acid on spot which meansin a catalytic amount and are therefore able to start the polymerizationthrough this acid. Such compounds which show such a property arecommonly known as photo-acid generator (PAG). PAG's are highly activeand have been shown to catalyze the deprotection of acid-sensitiveorganic functional groups with good photospeeds. PAG's are very oftenused in resists.

Another object of the invention is therefore a curable compositioncomprising at least one compound of formula I with cations of formula(2), (5), (6), (9), tritylium, pyrylium, 1-benzopyrylium or2-benzopyrylium as described before and at least one polymerizablecompound.

Another object of the invention is therefore a curable compositioncomprising at least one compound of formula I with cations of formula(2) and (9) as described or preferably described before and at least onepolymerizable compound.

The compounds of formula I with organic cations, e.g. ionic liquidsaccording to this invention may be preferably used in electrochemicaland/or optoelectronic devices, especially in electrolyte formulations.

The present invention therefore relates furthermore to an electrolyteformulation comprising at least one compound of formula I as describedabove or preferably described.

Electrolyte formulations comprising compounds of formula I in which[Kt]^(z+) is an organic cation can be preferably used in electrochemicalcells, optionally also in combination with further conductive saltsand/or additives, as constituent of a polymer electrolyte orphase-transfer medium.

Electrolyte formulations comprising compounds of formula I can bepreferably used in electrochemical and/or optoelectronic devices such asa photovoltaic cell, a light emitting device, an electrochromic orphoto-electrochromic device, an electrochemical sensor and/or biosensor,particularly preferred in a dye sensitised solar cell.

Such electrolyte formulations form a crucial part of the discloseddevices and the performance of the device largely depends on thephysical and chemical properties of the various components of theseelectrolytes.

Factors which are still impeding the technical application of manyelectrochemical and/or optoelectronic devices and in particular of dyeor quantum dot sensitized solar cells, are reliability problems causedby the volatility of organic solvents based electrolytes. It is verydifficult to maintain a tight sealing of the electrolyte in e.g. a DSCpanel, which has to withstand the temperature differences of dailyday-night cycles and the concomitant thermal expansion of theelectrolyte. The abbreviation DSC means dye sensitized solar cell. Thisproblem can be solved in principle by the use of ionic liquid-basedelectrolytes. For review “Ionic liquid electrolytes for dye-sensitizedsolar cells” see: William R Pitner et al., “Application of Ionic Liquidsin Electrolyte System” Green Chemistry. vol. 6, (2010).

Ionic liquids or liquid salts are typically ionic species which consistof an organic cation and a generally inorganic anion usually havingmelting points below 373 K. Various binary ionic liquid electrolyteshave recently been applied to dye-sensitized solar cells. WO 2007/093961and WO 2009/083901 describe so far the best power conversionefficiencies in ionic liquid-based electrolytes for DSC containing asignificant quantity of organic salts with tetracyanoborate (TCB)anions.

Electrolyte formulations according to the invention are alternatives toalready known electrolyte formulations. They show especially in thefield of electrolyte formulations of dye sensitised solar cells a goodperformance particularly under high temperature. The advantage of theuse of compounds of formula I having an organic cation and ahydrido-tricyano-borate anion is their low viscosity and high thermalstability.

In chemistry, an electrolyte is any substance containing free ions thatmake the substance electrically conductive. The most typical electrolyteis an ionic solution, but molten electrolytes and solid electrolytes arealso possible. An electrolyte formulation according to the invention istherefore an electrically conductive medium, basically due to thepresence of at least one substance that is present in a dissolved and orin molten state and undergo dissociation into ionic species, i.e.supporting an electric conductivity via motion of ionic species.However, the said electric conductivity may not be of the majorrelevance to the role of the electrolyte of a dye-sensitised solar cell.Therefore, the scope of this invention is not limited to highlyconductive electrolyte media.

The term electrolyte may be used for the term electrolyte formulation aswell comprising all ingredients as disclosed for the electrolyteformulation.

The electrolyte formulations according to the invention may include orcomprise, essentially consist of or consist of the said necessary oroptional constituents. All compounds or components which can be used inthe agents or compositions are either known and commercially availableor can be synthesized by known processes.

Typical molar concentrations of the hydridotricyanoborate compound inthe electrolyte formulations range from 0.1 to 5.5 M, preferably from0.8 to 3.5 M. This molar concentration in the electrolyte may beachieved with one or more compounds of formula I in which Kt^(z+) has ameaning as described or preferably described above.

Preferably, the molar concentration is achieved with at least onecompound of formula I as described or preferably described above.

For the purpose of the present invention, the molar concentration referto the concentration at 25° C.

The present invention relates furthermore to an electrolyte formulationcomprising at least one compound of formula (1) as described above orpreferably described together with redox active species such asiodide/tri-iodide, Ferrocene derivatives or Co(II)/Co(III) complexecouples such as Co(II)/Co(III)(dbbip)₂ in which dbbip means2,6-bis(1′-butylbenzimidazol-2′-yl)pyridine, Co(II)/Co(III)(bpy)₃ wherebpy denotes bipyridine or alkylated bipyridine derivates thereof,Co(II)/Co(III)(dmb)₃ where dmb denotes 4,4′-dimethyl-2,2′-bipyridine,Co(II)/Co(III)(dtb)₃ where dtb denotes4,4′-di-tert-butyl-2,2′-bipyridine, Co(II)/Co(III)(phen)₃ where phendenotes 1,10-phenanthroline, preferably a redox couple of iodine and atleast one iodide salt.

The electrolyte formulation of the invention preferably comprises iodine(I₂). Preferably, it comprises from 0.0005 to 7 mol/dm³, more preferably0.01 to 5 mol/dm³ and most preferably from 0.05 to 1 mol/dm³ of I₂.

The iodide salt consists of an inorganic or organic cation and I⁻ asanion. There exists no limitation to the kind of cation. However, tolimit the amount of different cations in the electrolyte formulations,especially for DSC, organic cations shall be used as already describedfor the compounds of formula I. Preferably, the electrolyte formulationcomprises at least one iodide salt in which the organic cation isindependently selected from the group of

in which the substituents

R^(2′) and R^(3′) each, independently of one another, denote H orstraight-chain or branched alkyl having 1 to 20 C atoms,

R^(1′) and R^(4′) each, independently of one another, denotestraight-chain or branched alkyl having 1-20 C atoms, which optionallymay be partially fluorinated or perfluorinated,

straight-chain or branched alkenyl having 2-20 C atoms and one or moredouble bonds, which optionally may be partially fluorinated,

straight-chain or branched alkynyl having 2-20 C atoms and one or moretriple bonds, which optionally may be partially fluorinated.

Particularly preferred examples of the at least one iodide salt are1-ethyl-3-methylimidazolium iodide (emim I),1-propyl-3-methylimidazolium iodide (pmim I),1-butyl-3-methyl-imidazolium iodide (bmim I),1-hexyl-3-methylimidazolium iodide (hmim I), 1,3-dimethyl-imidazoliumiodide (mmim I), 1-allyl-3-methylimidazolium iodide (amim I),N-butyl-N-methyl-pyrrolidinium iodide (bmpl I) orN,N-dimethyl-pyrrolidinium iodide (mmpl I).

Other components of the electrolyte formulation are one or severalfurther salts, solvents, and others, as indicated further below.

If the electrolyte formulation is a binary system, it comprises twosalts, one further salt or iodide salt and a compound of formula I asdescribed above. If the electrolyte formulation is a ternary system, itcomprises two further salts and/or iodide salts and a compound offormula I as described above. The binary system comprises 90-10 weight%, preferably 70-30 weight %, more preferably 55-40 weight % of thefurther salt or iodide salt and 10-90 weight %, preferably 30-70 weight% or more preferably 45-60 weight % of the compound of formula I asdescribed above. The percentages in this paragraph are expressed withrespect to the total of salts (=100 weight %) present in the electrolyteformulation according to the invention. Amounts of further, generallyoptional components (additives) indicated below, such as N-containingcompounds having unshared electron pairs, iodine, solvents, polymers,and nanoparticles, for example, are not considered therein. The samepercentages apply to ternary or quaternary systems which means the totalof the further salts has to be used in the given ranges, e.g. twofurther ionic liquids are comprised in e.g. 90-10 weight. % in theelectrolyte formulation according to the invention.

According to another embodiment of the present invention, theelectrolyte formulation comprises at least one further salt with organiccations comprising a quaternary nitrogen and an anion selected from ahalide ion, such as F⁻, Cl⁻, a polyhalide ion, a fluoroalkanesulfonate,a fluoroalkanecarboxylate, a tris(fluoroalkylsulfonyl)methide, abis(fluoroalkylsulfonyl)imide, bis(fluorosulfonyl)imide, a nitrate, ahexafluorophosphate, a tris-, bis- andmono-(fluoroalkyl)fluorophosphate, a tetrafluoroborate, a dicyanamide, atricyanomethide, a tetracyanoborate, a thiocyanate, an alkylsulfonate oran alkylsulfate, with fluoroalkane-chain having 1 to 20 C atoms,preferably perfluorinated, fluoroalkyl having 1 to 20 C atoms and alkylhaving 1 to 20 C atoms. Fluoroalkane-chain or fluoroalkyl is preferablyperfluorinated.

Preferably, the further salts are selected from salts comprising anionssuch as thiocyanate, tetracyanoborate and/or bis(fluorosulfonyl)imide,particularly preferred further salts are tetracyanoborates.

The cation of the at least one further salt or of a preferred furthersalt may be selected amongst organic cations as defined above for thecompounds of formula I including also the preferred meanings.

In another embodiment of the invention, guanidinium thiocyanate may beadded to the electrolyte formulation according to the invention.

In a preferred embodiment, the electrolyte formulation of the presentinvention further comprises at least one compound containing a nitrogenatom having non-shared electron pairs. Examples of such compounds arefound in EP 0 986 079 A2, starting on page 2, lines 40-55, and againfrom page 3, lines 14 extending to page 7, line 54, which are expresslyincorporated herein by reference. Preferred examples of compounds havingnon-shared electron pairs include imidazole and its derivatives,particularly benzimidazole and its derivatives.

The electrolyte formulation of the present invention may comprise anorganic solvent. Preferably, the electrolyte formulation comprises thecompound comprising a hydridotricyanoborate anion in the range between5% to 70% and the organic solvent in the range between 70% to 0% basedon the total weight of the formulation. Particularly preferably, theelectrolyte formulation comprises less than 50% of an organic solvent orless than 40%, more preferably less than 30%, still more preferably lessthan 20% and even less than 10%. Most preferably, the electrolyteformulation comprises less than 5% of an organic solvent. For example,it is substantially free of an organic solvent. Percentages areindicated on the basis of weight %.

Organic solvents, if present in such amounts as indicated above, may beselected from those disclosed in the literature. Preferably, thesolvent, if present, has a boiling point higher than 160 degreescentigrade, more preferably higher than 190 degrees such as propylenecarbonate, ethylene carbonate, butylene carbonate, gamma-butyrolactone,gamma-valerolactone, glutaronitrile, adiponitrile,N-methyloxazolidinone, N-methylpyrrolidinone,N,N′-dimethylimidazolidinone, N,N-dimethylacetamide, cyclic ureaspreferably 1,3-dimethyl-2-imidazolidinone or1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone, glymes preferablytetraglyme, sulfolane, sulfones which are preferably asymmetricallysubstituted such as 2-ethanesulfonyl-propane,1-ethanesulfonyl-2-methyl-propane or 2-(propane-2-sulfonyl)-butane,3-methylsulfolane, dimethylsulfoxide, trimethylphosphate andmethoxy-substituted nitriles. Other useful solvents are acetonitrile,benzonitrile and or valeronitrile. Preferred organic solvents aregamma-butyrolactone and tetraglyme.

If a solvent is present in the electrolyte formulation, there mayfurther be comprised a polymer as gelling agent, wherein the polymer ispolyvinylidenefluoride, polyvinylidene-hexafluoropropylene,polyvinylidene-hexafluoropropylene-chlorotrifluoroethylene copolymers,nafion, polyethylene oxide, polymethylmethacrylate, polyacrylonitrile,polypropylene, polystyrene, polybutadiene, polyethyleneglycol,polyvinylpyrrolidone, polyaniline, polypyrrole, polythiophene. Thepurpose of adding these polymers to electrolyte formulations is to makeliquid electrolytes into quasi-solid or solid electrolytes, thusimproving solvent retention, especially during aging.

The electrolyte formulation of the invention may further comprise metaloxide nanoparticles like SiO₂, TiO₂, Al₂O₃, MgO or ZnO, for example,which are also capable of increasing solidity and thus solventretention.

The electrolyte formulation of the invention has many applications. Forexample, it may be used in an optoelectronic and/or electrochemicaldevice such as a photovoltaic cell, a light emitting device, anelectrochromic or photo-electrochromic device, an electrochemical sensorand/or biosensor.

The present invention therefore relates further to the use of theelectrolyte formulation as described in detail above in anelectrochemical and/or optoelectronic device which is a photovoltaiccell, a light emitting device, an electrochromic or photo-electrochromicdevice, an electrochemical sensor and/or biosensor. Preferably, theelectrolyte formulation may be used in dye sensitized solar cells.

The present invention therefore relates furthermore to anelectrochemical and/or optoelectronic device which is a photovoltaiccell, a light emitting device, an electrochromic or photo-electrochromicdevice, an electrochemical sensor and/or biosensor comprising anelectrolyte formulation comprising at least one compound of formula I asdescribed or preferably described above.

Preferably, the compound of formula I is a compound of formula I inwhich [Kt]^(Z+) is an organic cation as described above including allpreferred meanings for application in dye-sensitized solar cells.

According to a preferred embodiment, the device of the present inventionis a dye or quantum dot sensitized solar cell, particularly preferably adye sensitized solar cell.

Quantum dot sensitized solar cells are disclosed in U.S. Pat. No.6,861,722, for example. In dye-sensitized solar cells, a dye is used toabsorb the sunlight to convert into the electrical energy. There are norestrictions per se with respect to the choice of the dye as long as theLUMO energy state is marginally above the conduction bandedge of thephotoelectrode to be sensitized. Examples of dyes are disclosed in EP 0986 079 A2, EP 1 180 774 A2 or EP 1 507 307 A1.

Preferred dyes are organic dyes such as MK-1, MK-2 or MK-3 (itsstructures are described in FIG. 1 of N. Koumura et al, J. Am. Chem.Soc. Vol 128, no. 44, 2006, 14256-14257), D102 (CAS no. 652145-28-3),D-149 (CAS no. 786643-20-7), D205 (CAS no. 936336-21-9), D358 (CAS no.1207638-53-6), YD-2 as described in T. Bessho et al, Angew. Chem. Int.Ed. Vol 49, 37, 6646-6649, 2010, Y123 (CAS no. 1312465-92-1),bipyridin-Ruthenium dyes such as N3 (CAS no. 141460-19-7), N719 (CAS no.207347-46-4), Z907 (CAS no. 502693-09-6), C101 (CAS no. 1048964-93-7),C106 (CAS no. 1152310-69-4), K19 (CAS no. 847665-45-6), HRS-1 (CAS no.906061-30-1 as disclosed in K. J. Jiang et al, Chem. Comm. 2460, 2006)or terpyridine-Ruthenium dyes such as N749 (CAS no. 359415-47-7).

The structure of D205 is

The structure of D358 is

Particularly preferred dyes are Z907 or Z907Na which are both anamphiphilic ruthenium sensitizer, C106, D358 or HRS-1. The dye Z907Nameans NaRu(2,2′-bipyridine-4-carboxylicacid-4′-carboxylate)(4,4′-dinonyl-2,2′-bipyridine)(NCS)₂.

Very particularly preferred dyes are Z907 or Z907Na and/or D358. Veryvery particularly preferred dyes are Z907 or Z907Na.

In a special embodiment, the dye is coadsorbed with a phosphinic acid. Apreferred example of a phosphinic acid isbis(3,3-dimethyl-butyl)-phosphinic acid (DINHOP) as disclosed in M. Wanget al, Dalton Trans., 2009, 10015-10020.

For example, a dye-sensitized solar cell comprises a photo-electrode, acounter electrode and, between the photo-electrode and the counterelectrode, an electrolyte formulation or a charge transporting material,and wherein a sensitizing dye is absorbed on the surface of thephoto-electrode, on the side facing the counter electrode.

According to a preferred embodiment of the device according to theinvention, it comprises a semiconductor, the electrolyte formulation asdescribed above and a counter electrode.

According to a preferred embodiment of the invention, the semiconductoris based on material selected from the group of Si, TiO₂, SnO₂, Fe₂O₃,WO₃, ZnO, Nb₂O₅, CdS, ZnS, PbS, Bi₂S₃, CdSe, GaP, InP, GaAs, CdTe,CuInS₂, and/or CuInSe₂. Preferably, the semiconductor comprises amesoporous surface, thus increasing the surface optionally covered by adye and being in contact with the electrolyte. Preferably, thesemiconductor is present on a glass support or plastic or metal foil.Preferably, the support is conductive.

The device of the present invention preferably comprises a counterelectrode. For example, fluorine doped tin oxide or tin doped indiumoxide on glass (FTO- or ITO-glass, respectively) coated with Pt, carbonof preferably conductive allotropes, polyaniline orpoly(3,4-ethylenedioxythiophene) (PEDOT). Metal substrates such asstainless steel or titanium sheet may be possible substrates besideglass.

The device of the present invention may be manufactured as thecorresponding device of the prior art by simply replacing theelectrolyte by the electrolyte formulation of the present invention. Forexample, in the case of dye-sensitized solar cells, device assembly isdisclosed in numerous patent literature, for example WO 91/16719(examples 34 and 35), but also scientific literature, for example inBarbé, C. J., Arendse, F., Comte, P., Jirousek, M., Lenzmann, F.,Shklover, V., Grätzel, M. J. Am. Ceram. Soc. 1997, 80, 3157; and Wang,P., Zakeeruddin, S. M., Comte, P., Charvet, R., Humphry-Baker, R.,Grätzel, M. J. Phys. Chem. B 2003, 107, 14336.

Preferably, the sensitized semi-conducting material serves as aphoto-anode. Preferably, the counter electrode is a cathode.

The present invention provides a method for preparing a photoelectriccell comprising the step of bringing the electrolyte formulation of theinvention in contact with a surface of a semiconductor, said surfaceoptionally being coated with a sensitizer. Preferably, the semiconductoris selected from the materials given above, and the sensitizer ispreferably selected from quantum dots and/or a dye as disclosed above,particularly preferably selected from a dye.

Preferably, the electrolyte formulation may simply be poured on thesemiconductor. Preferably, it is applied to the otherwise completeddevice already comprising a counter electrode by creating a vacuum inthe internal lumen of the cell through a hole in the counter electrodeand adding the electrolyte formulation as disclosed in the reference ofWang et al., J. Phys. Chem. B 2003, 107, 14336.

The present invention will now be illustrated, without limiting itsscope, by way of the following examples. Even without further comments,it is assumed that a person skilled in the art will be able to utilisethe above description in the broadest scope. The preferred embodimentsand examples should therefore merely be regarded as descriptivedisclosure which is absolutely not limiting in any way.

The substances are characterised by means of Raman and NMR spectroscopyand X-Ray analysis. The NMR-spectra are measured in deuterated solventsAceton-D₆ or CD₃CN by use of Bruker Avance III Spektrometer withDeuterium Lock. The resonance frequency for different nuclea are: ¹H:400.17 MHz, ¹¹B: 128.39 MHz, ³¹P: 161.99 MHz und ¹³C: 100.61 MHz. Thefollowing references are used: TMS für ¹H und ¹³C spectra and BF₃.Et₂O—for ¹¹B spectra.

EXAMPLES Example 1 Potassium hydrido-tricyano-borate—K[BH(CN)₃]

2Na[BH₄]+3{4KSCN+K₂[Zn(SCN)₄]}→2K[BH(CN)₃]+3ZnS+3H₂S+2NaSCN+16KSCN

The mixture of 1.08 g (28.5 mmol) NaBH₄ and 27 g (3.04 mol){4KSCN+K₂[Zn(SCN)₄]} is heated for 5 hours at 185° C. under vacuum.After cooling to room temperature, the reaction mixture is dissolved in200 cm³ water and the precipitate of ZnS is filtered off. The solutionis treated with 100 cm³ of 36%-ige HCl and water is distilled of invacuum at 50-60° C. The residue is extracted with 250 cm³ oftetrahydrofuran and non-soluble precipitant is filtered off. The solventis evaporated in vacuum and residue is dissolved in 100 cm³ of water.After filtration and treatment with 50 cm³ of 36%-ige HCl, the solutionis evaporated in vacuum at 50-60° C. The residue is dissolved in 150 cm³of acetonitrile. The solution is filtered and evaporated in vacuum. Theresidue is dissolved in 50 cm³ of 36%-ige HCl. The solution is leftstirring for 12 hours and is evaporated in vacuum at 50-60° C. Theresidue is dissolved in 10 cm³ of water. The solution is neutralizedwith K₂CO₃ and filtered. The product is extracted from this solutionwith tetrahydrofuran (50+20+20 cm³). The THF solution is dried withK₂CO₃ and evaporated. The residue is dried in vacuum. 0.43 g ofK[BH(CN)₃] is obtained. The product contains of about 10-15%K[BH₂(CN)₂].

Further purification can be achieved by treatment with 36%-ige HClwithin 15 hours at 100° C. followed by extraction with acetonitrile.

K[BH(CN)₃]: a=4.0558(3), b=8.6645(5), c=9.3318(8) Å, α=104.127(7),β=100.542(7), γ=90.110(5)°, V=312.27, Z=2, P-1, t=150K.

Example 2 Potassium hydrido-tricyano-borate—K[BH(CN)₃]

To 21.0 g (136 mmol) K[B(CN)₄] and 6.3 g (274 mmol) of Na ca. 100 cm³ ofliquid ammonia is condensed by cooling of the reaction vessel with dryice (−78° C.). The reaction mixture is slowly warmed up to −40 to −30°C. (temperature in the cooling bath) until the exothermic reactionstarts. The reaction mixture formed two phases: upper layer haddeep-blue colour of the Na solution in NH₃; bottom layer had red-orangecolour of Na₂[B(CN)₃] in NH₃. Within 30-50 min the deep-blue colourpractically completely disappeared. This indicated that reaction iscompleted. The reaction mixture is slowly warmed up in inert atmosphere(Ar) to the room temperature resulting in ammonia evaporation. Theresidue is pumped for ca. 10 min in vacuum (to remove the traces ofammonia) and treated with 100 cm³ of water. Within ca. 30 min at roomtemperature (if the traces of non-reacted Na is remained in the reactionmixture, the cooling of the reaction vessel is recommended) the yellowcolour of solid Na₂[B(CN)₃] disappeared and transparent colour-lesssolution in water is formed. The volume of the reaction mixture isreduced to 40-50 cm³. The residue is treated with 22 g K₂CO₃ and 100 cm³of tetrahydrofurane (THF). The THF-phase is separated and the waterphase is extracted two times with 50 cm³ of tetrahydrofurane. Thecombined THF-solution is dried with K₂CO₃, filtrated and the sovent isevaporated. The residue is washed with CH₂Cl₂ (2×50 cm³) and dried invacuum. The yield of K[BH(CN)₃] is 17.6 g (100%).

¹¹B-NMR: δ, ppm=−40.2 d, ¹J_(B,H)=98 Hz.

¹H{¹¹B}-NMR (Solvent: Acetonitrile-D₃): δ, ppm=1.77 s (BH, 1H).

Raman-spectrum, ν, cm⁻¹, K[HB(CN)₃]:

2462 s, 2430 m, 2235 s, 2222 vs, 1058 w, 728 w, 522 w, 498 vw, 348 s,180 s, 171s.

Example 3 Potassium hydrido-tricyano-borate—K[BH(CN)₃]

K[B(CN)₄]+KOH.0.55H₂O→K[BH(CN)₃]+KCN

A mixture of 10 g (65 mmol) K[B(CN)₄] and 22 g (334 mmol) KOH.0.55H₂O in20 cm³ of diglyme is stirred and heated for 80 min at 160-165° C. Aftercooling to room temperature the reaction mixture is dissolved in 40 cm³of water and product is extracted with tetrahydrofuran (3×100 cm³). TheTHF-extract is dried with K₂CO₃, filtered and all volatile components ofthe mixture are removed in vacuum. The residue is treated with 100 cm³of 36%-ige HCl and the solution is evaporated in vacuum at 50-60° C. Theresidue is dissolved in 50 cm³ of acetonitrile and 50 cm³ CH₂Cl₂ areadded to this solution. The mixture is filtered and diluted with 450 cm³of CH₂Cl₂. The precipitant (K[BH(CN)₃].xCH₃CN) is filtered off andwashed with CH₂Cl₂. The product, K[BH(CN)₃].xCH₃CN, is dried in vacuumat 50° C. for 15 hours. Yield of solid K[BH(CN)₃] is 6.0 g (72%).

The product is characterized by means of NMR spectroscopy. The ¹¹B-NMRand ¹H{¹¹B}-NMR spectra are identical to in Example 2 described spectra

Example 4 Synthesis of M₂[B(CN)₃], (M=Li, Na, K)

M[B(CN)₄]+2M→M₂[B(CN)₃]+MCN M=Li,Na,K30 mmol of M[B(CN)₄] (Merck KGaA, Darmstadt) and 60 mmol M (M=Li, Na orK) are placed into 100 cm³ glass flask under inert atmosphere(glove-box). Ca. 30 cm³ of liquid ammonia are condensed to this mixtureby cooling of reaction vessel with dry ice (−78° C.). The temperature ofthe reaction mixture is slowly increased to −40° C. (temperature in thecooling bath) until an exothermal reaction was started. During thereaction the blue colour of alkali-metal solution in ammonia disappearedand yellow precipitant was formed from orange solution. The reactiontime for K is of about 30 min; for Na is ca. 1 hour and for Li-2 hours.The side product, MCN, can be washed out with liquid ammonia (in thecase of M=K or Na) at −78° C. or with tetrahydrofuran in the case ofLiCN. The residue, practically pure M₂[B(CN)₃], is dried in the vacuumat room temperature.

Raman-spectrum, ν, cm⁻¹:

Na₂[B(CN)₃]: 2105 vs, 2040 s, 2013 vs, 1993 vs, 1154 w, 1113 w, 577/552m, 506 w, 174 vs

K₂[B(CN)₃]: 2098 vs, 2040 s, 2022 vs, 1997 vs, 1137 w, 1115 w, 561/551m, 502 w, 194 vs

NMR-spectra of [B(CN)₃]²⁻ dianion (Solvent: ND₃, at −40° C.; Referencesubstance

K[B(CN)₄]: δ(¹¹B)=−38.6 ppm and δ(¹³C)=122.3 ppm):

NMR ¹¹B, δ, ppm: −45.3, ¹J(¹¹B, ¹³C)=92 Hz

NMR ¹³C, δ, ppm: 157.7, ¹J(¹¹B, ¹³C)=93 Hz

K₂[B(CN)₃] is decomposed above 230° C. (DSC onset) exothermally withcolouring (brown).

The yellow salts M₂[B(CN)₃] hydrolyze quantitatively with water to thecorresponding hydrido-tricyano borates, M[BH(CN)₃] which can be isolatedfrom aqueous solution as pure salts in quantitative yield.M₂[B(CN)₃]+H₂O→M[HB(CN)₃]+MOH (M=Li,Na,K)

Example 5 1-ethyl-3-methylimidazoliumhydrido-tricyano-borate—[EMIM][BH(CN)₃]

10.0 g (79 mmol) K[BH(CN)₃] dissolved in 50 cm³ water and 11.6 g (79mmol) 1-ethyl-3-methylimidazolium chloride, [EMIM]Cl in 50 cm³ water aremixed together at room temperature. The product,1-ethyl-3-methylimidazolium tricyanohydridoborate is extracted withdichloromethane (100+50+50 cm³ of CH₂Cl₂). The organic phase is washedtwo times with water (50+50 cm³) and dried with Na₂SO₄. The solvent isdistilled off and the residue is dried in vacuum at ca. 40° C. for 15hours. The yield of liquid at room temperature1-ethyl-3-methylimidazolium tricyanohydridoborate, [EMIM] [BH(CN)₃], is12.2 g (77%).

-   Residual water: 15 ppm.-   Chloride impurities: 9 ppm (ion-chromatography)-   Viscosity: 12.2 mPa·s (20° C.).-   Decomposition temperature: above 277° C. (DSC/TGA; onset).

¹H{¹¹B}-NMR (Solvent: Acetonitrile-D₃): δ, ppm=1.49 t (CH₃, 3H),³J_(H,H)=7.3 Hz; 1.77 s (BH, 1H); 3.86 s (CH₃, 3H); 4.20 q (CH₂, 2H),³J_(H,H)=7.3 Hz; 7.36 d,d (CH, H); 7.42 d,d (CH, H), ³J_(H,H)=1.7 Hz;8.46 br.s (CH, 1H).

¹¹B-NMR (Solvent: Acetonitrile-D₃): δ, ppm=−40.2 s, ¹J_(B,H)=97 Hz.

Example 6 1-butyl-1-methylpyrrolidiniumhydrido-tricyano-borate—[BMPL][BH(CN)₃]

7.3 g (57 mmol) K[BH(CN)₃] dissolved in 20 cm³ water and 10.1 g (57mmol) 1-butyl-1-methylpyrrolidinium chloride, [BMPL]Cl in 20 cm³ waterare mixed together at room temperature. The product,1-butyl-1-methylpyrrolidinium tricyanohydridoborate, is extracted withdichloromethane (100+50+50 cm³ of CH₂Cl₂). The organic phase is washedtwo times with water (50+50 cm³) and dried with Na₂SO₄. The solvent isdistilled off and the residue is dried in vacuum at ca. 45° C. for 16hours. The yield of liquid at room temperature1-butyl-1-methylpyrrolidinium tricyanohydridoborate, [BMPL] [BH(CN)₃],is 12.6 g (96%).

¹H{¹¹B}-NMR (Solvent: Acetonitrile-D₃): δ, ppm=0.98 t (CH₃, 3H),³J_(H,H)=7.3 Hz; 1.40 t.q (CH₂, 2H), ³J_(H,H)=7.4 Hz, 1.70-1.80 m (CH₂,2H); 1.79 s (BH, 1H), 2.18 m (2CH₂, 4H); 2.98 s (CH₃, 3H); 3.26 m, (CH₂,2H); 3.44 m (2CH₂, 4H).

¹¹B-NMR (Solvent: Acetonitrile-D₃): δ, ppm=−40.1 s, ¹J_(B,H)=98 Hz.

Viscosity: 26.6 mPa·s (20° C.).

Decomposition temperature: above 280° C. (DSC/TGA; onset).

Example 7 N,N,N-tri-n-butyl-N-methylammoniumhydrido-tricyano-borate—[n-Bu₃NCH₃] [BH(CN)₃]

8.84 g (68.5 mmol) K[BH(CN)₃] dissolved in 50 cm³ water and 16.2 g (68.7mmol) N,N,N-tri-n-butyl-N-methylammonium chloride, [n-Bu₃NCH₃]Cl in 50cm³ water are mixed together at room temperature. The product,N,N,N-tri-n-butyl-N-methylammonium tricyanohydridoborate is extractedwith dichloromethane (100+50+50 cm³ of CH₂Cl₂). The organic phase iswashed two times with water (50+50 cm³) and dried with Na₂SO₄. Thesolvent is distilled off and the residue is dried in vacuum at ca. 45°C. for 1 day. The yield of liquid at room temperatureN,N,N-tri-n-butyl-N-methylammonium tricyanohydridoborate,[n-Bu₃NCH₃][BH(CN)₃], is 16.4 g (82%).

Content of chloride impurities: 24 ppm (ion-chromatography).

Viscosity: 149 mPa·s (20° C.).

¹H{¹¹B}-NMR (Solvent: Aceton-D₆): δ, ppm=1.00 t (3CH₃, 9H), ³J_(H,H)=7.4Hz; 1.43 m (3CH₂, 6H); 1.80 s (BH, 1H), 1.75-1.86 m (3CH₂, 6H); 3.15 s(CH₃, 3H), 3.40 m, (3CH₂, 6H).

¹¹B-NMR (Solvent: Aceton-D₆): δ, ppm=−40.0 d, ¹J_(B,H)=97 Hz.

Example 8 tetra-n-butylphosphoniumhydrido-tricyanoborate—[n-Bu₄P][BH(CN)₃]

1.93 g (15.0 mmol) K[BH(CN)₃] dissolved in 10 cm³ of water are mixed atroom temperature with 10.4 g (10.5 cm³, 15.0 mmol) 40% aqueous solutiontera-n-butylphosphonium hydroxyde, [n-Bu₄P]OH. The product,tera-n-butylphosphonium tricyanohydrido-borate is extracted withdichloromethane (100+50+50 cm³ of CH₂Cl₂). The organic phase is washedtwo times with water (50+50 cm³) and dried with Na₂SO₄. The solvent isdistilled off and the residue is dried in vacuum at ca. 45° C. for 2day. The yield of liquid at room temperature tera-n-butylphosphoniumtricyanohydridoborate, [n-Bu₄P][BH(CN)₃], is 4.86 g (89%).

¹H{¹¹B}-NMR (Solvent: Aceton-D₆): δ, ppm=0.98 t (4CH₃, 12H),³J_(H,H)=7.3 Hz; 1.53 m (4CH₂, 8H); 1.62-1.74 m (4CH₂, 8H); 1.80 s (BH,1H), 2.36 m, (4CH₂, 8H).

¹¹B-NMR (Solvent: Aceton-D₆): δ, ppm=−40.0 d, ¹J_(B,H)=97 Hz.

Example 9 1-butyl-3-methylpyridiniumhydrido-tricyano-borate—[BMPy][BH(CN)₃]

8.08 g (62.7 mmol) K[BH(CN)₃] dissolved in 35 cm³ of water and 11.63 g(62.6 mmol) of 1-butyl-3-methylpyridinium chloride, [BMPy]Cl, dissolvedin 18 cm³ of water are mixed together at room temperature. The product,1-butyl-3-methylpyridinium tricyanohydridoborate is extracted withdichloromethane (100+50+50 cm³ of CH₂Cl₂). The organic phase is washedtwo times with water (50+50 cm³) and dried with Na₂SO₄. The solvent isdistilled off and the residue is dried in vacuum at ca. 40° C. for oneday. The yield of liquid at room temperature 1-butyl-3-methylpyridiniumtricyanohydridoborate, [BMPy][BH(CN)₃], is 13.64 g (91%).

¹H-NMR (Solvent: Aceton-D₆): δ, ppm=0.99 t (CH₃, 3H), ³J_(H,H)=7.5 Hz;1.45 m (CH₂, 2H); 1.74 d (1H, BH), ¹J_(H,B)=97 Hz; 2.09 m (CH₂, 2H);2.63 s (CH₃, 3H), 4.72 t (CH₂, 2H), ³J_(H,H)=7.6 Hz; 8.10 d,d (CH, 1H),³J_(H,H)=7.0 Hz; 8.50 d (CH, 1H), ³J_(H,H)=8.0 Hz; 8.88 d (CH, 1H),³J_(H,H)=6.1 Hz; 8.94 s (CH, 1H).

¹¹B-NMR (Solvent: Aceton-D₆): δ, ppm=−40.1 d, ¹J_(B,H)=97 Hz.

Example 10 triethyl-sulfonium hydrido-tricyano-borate,[(C₂H₅)₃S]⁺[BH(CN)₃]⁻

K[BH(CN)₃]+[(C₂H₅)₃S]l+AgCl→[(C₂H₅)₃S][BH(CN)₃]+KCl+Agl

The solution of 52.34 g (308 mmol) AgNO₃ in 200 mL of water is treatedwith 27 mL 37% HCl. Precipitant (AgCl) is filtered off and washed 5 timewith 200 mL of water. AgCl obtained in this way is vigorously stirredfor 24 hours with 14.45 g (58.7 mmol) of triethyl sulfonium iodide,[Et₃S]I, in 50 mL of water. The yellow precipitant is filtered off andthe aqueous solution of triethyl sulfonium chloride, [Et₃S]Cl, isreacted with 7.61 g (59.0 mmol) of potassium hydrido-tricyano-borate,K[BH(CN)₃]. The reaction mixture is extracted with 100+50+50 mL CH₂Cl₂.The organic phase is washed with 10+10+10 mL of water and dried withNa₂SO₄. The solution is filtered and the solvent is distilled off. Theresidue is dried in vacuum at 40-50° C. over night. 10.50 g (50.2 mmol)of liquid triethylsulfonium hydrido-tricyano-borate, [Et₃S][BH(CN)₃], isobtained Yield is 86% calculating on the triethyl sulfonium iodide used.The product is characterised with the NMR spectra.

[BH(CN)₃]⁻

¹H-NMR (Solvent: CD₃CN), δ, ppm: 1.79 q, ¹J(¹H,¹¹B)=98 Hz.

¹¹B-NMR (Solvent: CD₃CN), δ, ppm: −40.1d, ¹J(¹H,¹¹B)=98 Hz,¹J(¹³C,¹¹B)=66 Hz.

¹³C-NMR (Solvent: CD₃CN), δ, ppm: 128.2 q,d, ¹J(¹³C,¹¹B)=66 Hz,¹J(¹H,¹³C)=13 Hz,

[(C₂H₅)₃S]⁺

¹H-NMR (Solvent: CD₃CN), δ, ppm: 1.43 t (CH₃), ³J_(H,H)=7.45 Hz,¹J_(H,C)=131 Hz; 3.23 q (CH₂), ³J_(H,H)=7.41 Hz, ¹J_(H,C)=146 Hz.

¹³C-NMR (Solvent: CD₃CN), δ, ppm: 9.0 q,m (CH₃), ¹J_(C,H)=131 Hz,²J_(C,H)=4 Hz; 33.3 μm (CH₂), ¹J_(C,H)=146 Hz, ^(2,3)J_(C,H)=2-4 Hz,¹J_(C,C)=34 Hz.

Viscosity and density of triethyl-sulfonium hydrido-tricyano-borate,[Et₃S][BH(CN)₃]:

Temperature, ° C. Viscosity, mPa · s Density, g/cm³ 20 14.65 0.981 408.45 0.967 60 5.50 0.954 80 3.87 0.941

Example 11 diphenyl-iodonium hydrido-tricyano-borate,[(C₆H₅)₂I]⁺[BH(CN)₃]⁻

K[BH(CN)₃]+[(C₆H₅)₂I]Cl.H₂O→[(C₆H₅)₂I][BH(CN)₃]+KCl+H₂O

The solution 0.90 g (6.98 mmol) of K[BH(CN)₃] in 10 mL H₂O and thesolution of 2.27 g (6.80 mmol) of diphenyl iodonium chloridemonohydrate, [Ph₂I]Cl.H₂O in 150 mL CH₂Cl₂ are mixed together. Thereaction mixture is diluted with 100 mL of water and two phase system isseparated in the funnel. The aqueous phase is additionally extracted twotimes with 20 mL CH₂Cl₂. The combined organic phase is washed with 50 mLof water and dried with Na₂SO₄. The solution is filtered and the solventis distilled off. The residue is dried in vacuum at 40-50° C. overnight. 2.35 g (6.34 mmol) of diphenyl-iodonium hydrido-tricyano-borate,[(C₆H₅)₂I][BH(CN)₃], is obtained. Yield is 93% calculating on thediphenyl iodonium chloride monohydrate used. The product ischaracterised with the NMR spectra.

[BH(CN)₃]⁻

¹H-NMR (Solvent: CD₃CN), δ, ppm: 1.90 q, ¹J(¹H,¹¹B)=98 Hz.

¹¹B-NMR (Solvent: CD₃CN), δ, ppm: −39.9 d, ¹J(¹H,¹¹B)=98 Hz.

¹³C-NMR (Solvent: CD₃CN), δ, ppm: 128.2 q,d, ¹J(¹³C,¹¹B)=66 Hz,¹J(¹H,¹³C)=13 Hz,

[(C₆H₅)₂I]⁺

¹H-NMR (Solvent: CD₃CN), δ, ppm: 7.55 t (CH, 4H), ³J_(H,H)=7.5 Hz, 7.69t (CH, 2H), ³J_(H,H)=7.5 Hz, 8.14 d,d (CH, 4H), ³J_(H,H)=8.5 Hz,⁴J_(H,H)=0.8 Hz.

¹³C-NMR (Solvent: CD₃CN), δ, ppm: 114.3 t,q (2C), J_(C,H)=11.9 Hz,J_(C,H)=2.1

Hz; 133.2 d,d (4C), ¹J_(C,H)=167 Hz, J_(C,H)=8.1 Hz; 133.7 d,t (2C),¹J_(C,H)=165 Hz, J_(C,H)=7.4 Hz; 136.0 d,m (4C), ¹J_(C,H)=169 Hz,J_(C,H)=7-8 Hz.

Example 12 ditolyl-iodonium hydrido-tricyano-borate,[(4-CH₃C₆H₄)₂I]⁺[BH(CN)₃]⁻

K[BH(CN)₃]+[(4-CH₃C₆H₄)₂I][PF₆]→[(C₆H₅)₂I][BH(CN)₃]+K[PF₆]

The solution 0.832 g (6.45 mmol) of K[BH(CN)₃] in 10 mL CH₃CN and thesolution of 2.680 g (5.90 mmol) of ditolyl-iodonium hexafluorophosphate,[(4-CH₃C₆H₄)₂I][PF₆], in 5 mL CH₃CN are mixed together. The precipitateis filtered off and the solution is evaporated on rotary evaporator. Theresidue is dissolved in 20 mL CH₂Cl₂, the precipitant is filtered offand washed with 10 mL CH₂Cl₂. The solvent is evaporated on rotaryevaporator and the residue is dried in vacuum at 40-50° C. over night.2.226 g (5.58 mmol) of ditolyl-iodonium hydrido-tricyano-borate,[(4-CH₃C₆H₄)₂I][BH(CN)₃], is obtained Yield is 95% calculating on theditolyl iodonium hexafluorophosphate used. The product is characterisedwith the NMR spectra.

[BH(CN)₃]⁻

¹H-NMR (Solvent: CD₃CN), δ, ppm: 1.85 q, ¹J(¹H,¹¹B)=99 Hz.

¹¹B-NMR (Solvent: CD₃CN), δ, ppm: −40.0 d, ¹J(¹H,¹¹B)=99 Hz.

¹³C-NMR (Solvent: CD₃CN), δ, ppm: 128.3 q,d, ¹J(¹³C,¹¹B)=66 Hz,¹J(¹H,¹³C)=13 Hz.

[(4-CH₃C₆H₄)₂I]⁺

¹H-NMR (Solvent: CD₃CN), δ, ppm: 2.38 s (CH₃, 3H); 7.36 d (CH, 4H),³J_(H,H)=8.3 Hz; 7.99 d (CH, 4H), ³J_(H,H)=8.4 Hz.

¹³C-NMR (Solvent: CD₃CN), δ, ppm: 21.4 q,t (2C, 2CH₃), ¹J_(C,H)=128 Hz,³J_(C,H)=4.2 Hz; 110.7 t (2C), J_(C,H)=12.0 Hz; 134.0 d,d,q (4C),¹J_(C,H)=164 Hz, J_(C,H)=5.8 Hz; 136.0 d,d (4C), ¹J_(C,H)=170 Hz,J_(C,H)=5.7 Hz; 145.2 t,q (2C), J_(C,H)=6.5 Hz.

Example A Formulations and Device

The following electrolyte formulations are synthesized to demonstratethe application of electrolyte formulations according to the inventionrelative to electrolyte formulations of the prior art containing emimTCB in dye sensitized solar cells.

The electrolyte formulations are prepared through mixing of one or moreof 1,3-dimethylimidazolium iodide (mmimI), 1-propyl-3-methylimidazoliumiodide (pmimI), iodine, N-butylbenzimidazole (NBB) and guanidiniumthiocyanate (guaSCN) and the corresponding ionic liquid as indicatedsuch as emim TCB and emim [BH(CN)₃] (emim MHB) or bmpl TCB and bmpl[BH(CN)₃] (N-butyl-N-methylpyrrolidinium monohydridotricyanoborate=bmplMHB) in weight % as listed below.

Electrolyte 1 molar ratio [%] theoretical value in weight % I₂ 3.1 3.5mmim I 22.4 22.0 pmim I 22.4 24.8 guaSCN 1.2 0.6 NBB 6.2 4.8 emim TCB44.7 44.3 total 100 100

Electrolyte 1 is measured three times.

molar ratio theoretical value in weight Electrolyte 2 [%] % I₂ 3.1 3.6mmim I 22.4 22.8 pmim I 22.4 25.7 guaSCN 1.2 0.7 NBB 6.2 4.9 emim[BH(CN)₃] 44.8 42.3 total 100 100

Electrolyte 2 is measured three times.

Electrolyte 3 weight % I₂ 1.3 mmim I 35 guaSCN 0.7 NBB 3 emim TCB 60total 100

Electrolyte 3 is measured two times.

Electrolyte 4 weight % I₂ 1.3 mmim I 35 guaSCN 0.7 NBB 3 emim [BH(CN)₃]60 total 100

Electrolyte 4 is measured two times.

Electrolyte 5 weight % I₂ 1.3 mmim I 35 guaSCN 0.7 NBB 3 bmpl TCB 60total 100

Electrolyte 5 is measured two times.

Electrolyte 6 weight % I₂ 1.3 mmim I 35 guaSCN 0.7 NBB 3 bmpl [BH(CN)₃]60 total 100

Electrolyte 6 is measured two times.

The above cited compounds are commercially available or are synthesizedaccording to known literature methods.

The dye sensitized solar cells for the following measurements(masterplates) are commercially available from ISE (Institut für solareEnergiesysteme, Freiburg), serial no. 010311 which are fabricated basedon the disclosure of U.S. Pat. No. 5,728,487 or WO 2007/093961:

The used titaniumdioxide paste is commercially available from Dyesol,Australia, serial no. DSL 18 NRT and DSL 18NRT AO.

The titanium dioxide is screen printed three times: two times with thetitaniumdioxide paste DSL 18 NRT (each layer thickness=2 μand one timewith the titaniumdioxide paste DSL 18NRT AO (layer thickness 5 to 6 μm).

The masterplate is irrigated with a solution of 30 mg Z907 dye in 62.5ml ethanol for 6 hours.

The electrolyte formulations as described above are filled into theinternal space of the prepared masterplate to produce the correspondingdevices.

The dye Z907 is an amphiphilic ruthenium sensitizer Ru(2,2′-bipyridine4,4′-dicarboxylic acid) (4,4′-dinonyl-2,2′-bipyridine)(NCS)₂ orsynonymously [Ru(H2dcbpy)(dnbpy)(NCS)₂].

The measurements of photocurrent-voltage curves are carried out underSolarsimulator Sun 2000 from Abet Technologies, Model 11018, withtemperature control for devices fabricated as described above containingelectrolytes 1 to 6 placed on a black plate chilled down to 25° C. under1 Sun illumination. The measured area of the solar cell is 5 mm to 25mm.

Energy conversion efficiency is generally the ratio between the usefuloutput of an energy conversion machine and the input of light radiation,in energy terms, determined by using adjustable resistant load tooptimize the electric power output.

Table 1 summarizes the results of the measurements of the above citedelectrolyte formulations as average values:

Electrolyte J_(SC) [mAcm⁻²] V_(OC) [V] FF [%] η [%] 1* 9.0  0.65 66.83.9 2  8.9  0.67 67.8 4.1 3* 7.2  0.62 57.5 2.6 4  7.85 0.62 60.8 3.0 5*4.65 0.62 54.5 1.6 6  5.1  0.62 53.5 1.7 *not according to the invention$\begin{matrix}{J_{SC} = {{short}\mspace{14mu}{circuit}\mspace{14mu}{current}}} \\{V_{OC} = {{open}\mspace{14mu}{circuit}\mspace{14mu}{voltage}}} \\{{FF} = {{fill}\mspace{14mu}{factor}}} \\{\eta = {{power}\mspace{14mu}{conversion}\mspace{14mu}{efficiency}}}\end{matrix}{\quad\quad}$

Table 1 documents that electrolytes comprising hydridotricyanoborate asanion perform better or equal than electrolytes comprising TCB as anionif the same cation is used.

Example B Formulations and Device

The following electrolyte formulations are synthesized to demonstratethe unexpected advantage of electrolyte formulations according to theinvention relative to electrolyte formulations of the prior artcontaining emim TCB.

The electrolyte formulations are prepared through mixing of one or moreof 1,3-dimethylimidazolium iodide (mmimI), 1-ethyl-3-methylimidazoliumiodide (emimI), 1-propyl-3-methylimidazolium iodide (pmimI),1-allyl-3-methylimidazolium iodide (allylMIMI), iodine,N-butylbenzimidazole (NBB), guanidinium thiocyanate (guaSCN),γ-butyrolacton (GBL) and tetraethylenglycoldimethylether (TG) and thecorresponding ionic liquid as indicated such as emim TCB, B3MPYR TCB(1-Butyl-3-methyl-pyridinium tetracyanoborate), emim [BH(CN)₃], bmpl[BH(CN)₃] (N-butyl-N-methylpyrrolidinium hydridotricyanoborate) orB3MPYR [BH(CN)₃] (1-Butyl-3-methyl-pyridinium hydridotricyanoborate) inweight % as listed below.

Electrolyte 7 weight % I₂ 3.5 pmim I 21 mmim I 20 guaSCN 0.5 NBB 5 emimTCB 25 GBL 25 total 100

Electrolyte 8 weight % I₂ 3.5 pmim I 21 mmim I 20 guaSCN 0.5 NBB 5 emimMHB 25 GBL 25 total 100

Electrolyte 9 weight % I₂ 3.5 pmim I 21 mmim I 20 guaSCN 0.5 NBB 5 emimTCB 25 TG 25 total 100

Electrolyte 10 weight % I₂ 3.5 pmim I 21 mmim I 20 guaSCN 0.5 NBB 5 emimMHB 25 TG 25 total 100

Electrolyte 11 weight % I₂ 4.1 emim I 27.9 mmim I 26.2 guaSCN 0.8 NBB5.7 emim TCB 35.3 total 100

Electrolyte 12 weight % I₂ 4.3 emim I 29.0 mmim I 27.2 guaSCN 0.8 NBB5.9 emim MHB 32.8 total 100

Electrolyte 13 weight % I₂ 4.3 emim I 15 mmim I 14.2 allylMIMI 15.1guaSCN 0.8 NBB 5.9 emim TCB 44.7 total 100

Electrolyte 14 weight % I₂ 4.3 emim I 15 mmim I 14.2 allylMIMI 15.1guaSCN 0.8 NBB 5.9 emim MHB 44.7 total 100

Electrolyte 15 weight % I₂ 3.5 pmim I 24.8 mmim I 22 guaSCN 0.6 NBB 4.8b3mpyr TCB 44.6 total 100

Electrolyte 16 weight % I₂ 3.5 pmim I 24.8 mmim I 22 guaSCN 0.6 NBB 4.8b3mpyr MHB 44.6 total 100

The above cited compounds are commercially available or are synthesizedaccording to known literature methods.

The dye sensitized solar cells for the following measurements(masterplates) are commercially available from ISE (Institut für solareEnergiesysteme, Freiburg), serial no. 010311 which are fabricated basedon the disclosure of U.S. Pat. No. 5,728,487 or WO 2007/093961:

The used titaniumdioxide paste is commercially available from Dyesol,Australia, serial no. DSL 18 NRT and DSL 18NRT AO.

The titanium dioxide is screen printed three times: two times with thetitaniumdioxide paste DSL 18 NRT (each layer thickness=2 μm) and onetime with the titaniumdioxide paste DSL 18NRT AO (layer thickness 5 to 6μm).

The masterplate is irrigated with a solution of 30 mg Z907 dye in 62.5ml ethanol for 4 hours.

The electrolyte formulations as described above are filled into theinternal space of the prepared masterplate to produce the correspondingdevices.

The dye Z907 is an amphiphilic ruthenium sensitizer Ru(2,2′-bipyridine4,4′-dicarboxylic acid) (4,4′-dinonyl-2,2′-bipyridine)(NCS)₂ orsynonymously [Ru(H2dcbpy)(dnbpy)(NCS)₂].

The measurements of photocurrent-voltage curves are carried out underSolarsimulator Sun 2000 from Abet Technologies, Model 11018, withtemperature control for devices fabricated as described above containingelectrolytes 7 to 14 placed on a black plate chilled down to 25° C.under 1 Sun illumination. The measured area of the solar cell is 5 mm to25 mm.

Energy conversion efficiency is generally the ratio between the usefuloutput of an energy conversion machine and the input of light radiation,in energy terms, determined by using adjustable resistant load tooptimize the electric power output.

Table 2 summarizes the results of the measurements of the above citedelectrolyte formulations as average values:

Electrolyte J_(SC) [mAcm⁻²] V_(OC) [V] FF [%] η [%]  7* 9.9 0.62 67.34.2  8  9.8 0.63 0.68 4.2  9* 8.3 0.62 0.61 3.1 10  8.5 0.63 0.59 3.211* 8.3 0.62 0.67 3.5 12  8.7 0.62 0.66 3.6 13* 7.5 0.61 0.66 3.0 14 7.3 0.61 0.67 3.0 15* 7.8 0.58 0.45 2.0 16  8.1 0.58 0.44 2.1 *notaccording to the invention $\begin{matrix}{J_{SC} = {{short}\mspace{14mu}{circuit}\mspace{14mu}{current}}} \\{V_{OC} = {{open}\mspace{14mu}{circuit}\mspace{14mu}{voltage}}} \\{{FF} = {{fill}\mspace{14mu}{factor}}} \\{\eta = {{power}\mspace{14mu}{conversion}\mspace{14mu}{efficiency}}}\end{matrix}\quad$

Table 2 documents that electrolytes comprising hydridotricyanoborate asanion perform better or comparable to electrolytes comprising TCB asanion if the same cation is used.

Example C Formulation and Device

The following electrolyte formulations are synthesized to demonstratethe unexpected advantage of electrolyte formulations according to theinvention (emim MHB) relative to corresponding electrolyte formulationscontaining emim TCB.

The electrolyte formulations are prepared through mixing of1,3-dimethylimidazolium iodide (mmimI), iodine, N-butylbenzimidazole(NBB), guanidinium thiocyanate (guaSCN) and the corresponding ionicliquid as indicated such as emim TCB, emim [BH(CN)₃] (emim MHB) ormixtures of emim TCB and emim MHB in weight % as listed below.

TABLE 3 electrolytes 11 to 15 Ingredients Electrolyte in weight % 17* 1819 20 21 I₂ 1.3 1.3 1.3 1.3 1.3 mmimI 35.0 35.0 35.0 35.0 35.0 guaSCN0.7 0.7 0.7 0.7 0.7 emim TCB 60.0 45.0 30.0 15.0 0.0 emim MHB 0.0 15.030.0 45.0 60.0 NBB 3.0 3.0 3.0 3.0 3.0 *not according to the invention

The dye sensitized solar cells are fabricated as disclosed in U.S. Pat.No. 5,728,487 or WO 2007/093961:

A double-layer, mesoporous TiO₂ electrode was prepared as disclosed inWang P et al., J. Phys. Chem. B 2003, 107, 14336, in particular page14337, in order to obtain a photoanode consisting of a double layerstructure. To prepare a transparent nanoporous TiO₂ electrode, a screenprinting paste containing terpineol solvent and nanoparticulate TiO₂ ofanatase phase with 20 nm diameter was deposited on a transparentconductive substrate to 5 mm×5 mm squared shape by using a hand printer.The paste was dried for 10 minutes at 120 degrees Celsius. Anotherscreen printing paste containing TiO₂ with 400 nm diameter was thendeposited on top of the nanoporous layer to prepare an opaque layer. Thedouble layer film was then sintered at 500 degrees Celsius for an hourwith the result of an underlying transparent layer (7 microns thick) anda top opaque layer (4 microns thick). After sintering, the electrode wasimmersed in 40 mM aqueous solution of TiCl₄ (Merck) for 30 minutes at 70degrees Celsius and then rinsed with pure water sufficiently. ThusTiCl₄-treated electrode was dried at 500 degrees Celsius for 30 minutesjust before dye sensitization. The electrode was dipped into a dyesolution being 0.3 mM for the dye C106 and 0.075 mM for DINHOP (solventmixture acetonitrile (Merck HPLC grade) and tert-butyl alcohol (Merck),v:v=1:1) for 64 hours at 6 degrees Celsius. The counter electrode wasprepared with thermal pyrolysis method as disclosed in the referenceabove. A droplet of 5 mM solution of platonic acid (Merck) was casted at8 ml/cm² and dried on a conductive substrate. The dye sensitized solarcell was assembled by using 30 micron thick Bynel (DuPont, USA) hot-meltfilm to seal up by heating. The internal space was filled with each ofthe electrolyte formulations as described above to produce thecorresponding devices.

In order to obtain accurate light intensity level, Air Mass 1.5 Global(AM 1.5G) simulated sunlight is calibrated spectrally according to SeigoIto et al, “Calibration of solar simulator for evaluation ofdye-sensitized solar cells”, Solar Energy Materials & Solar Cells, 82,2004, 421.

The measurements of photocurrent-voltage curves are carried out underAir Mass 1.5 simulated sunlight (AM 1.5) with temperature control fordevices fabricated as described above containing electrolytes 1 to 4placed on a black plate chilled down to 25° C. under 1 Sun illumination.A photomask of 4 mm×4 mm is placed on top of the devices to define thelight projection area. The cell gap is around 20 micron.

Energy conversion efficiency is generally the ratio between the usefuloutput of an energy conversion machine and the input of light radiation,in energy terms, determined by using adjustable resistant load tooptimize the electric power output.

Table 4-A summarizes the results of the measurements of the above citedelectrolyte formulations:

Electrolyte J_(SC) [mAcm⁻²] V_(OC) [V] FF η [%] 17* 11.03 0.72 0.73 5.7218  10.00 0.74 0.68 5.03 19  11.41 0.74 0.73 6.14 20  11.35 0.74 0.746.25 21  12.14 0.73 0.76 6.82 *not according to the invention$\begin{matrix}{J_{SC} = {{short}\mspace{14mu}{circuit}\mspace{14mu}{current}}} \\{V_{OC} = {{open}\mspace{14mu}{circuit}\mspace{14mu}{voltage}}} \\{{FF} = {{fill}\mspace{14mu}{factor}}} \\{\eta = {{power}\mspace{14mu}{conversion}\mspace{14mu}{efficiency}}}\end{matrix}\quad$

Table 4-A documents that electrolytes comprisingmonohydridotricyanoborate as anion or electrolytes comprising mixturesof monohydridotricyanoborate and tetracyanoborate anions perform betterthan electrolytes comprising TCB as anion if the same cation is used.

The performance of a heat stress test (85° C.) for electrolytes of table4 documents that the electrolytes 18, 19 and 20 have the high efficiencyof the inventive monohydridotricyanoborate and the high stability oftetracyanoborate.

The dye sensitized solar cells are fabricated and measured as disclosedbefore but with the dye Z907 without the additive DINHOP.

Table 4-B summarizes the results of the measurements of the above citedelectrolyte formulations:

Electrolyte J_(SC) [mAcm⁻²] V_(OC) [V] FF η [%] 17* 10.63 0.71 0.64 4.8418  11.66 0.72 0.66 5.55 19  11.96 0.71 0.68 5.79 20  12.41 0.71 0.686.03 21  11.63 0.73 0.70 5.88 *not according to the invention$\begin{matrix}{J_{SC} = {{short}\mspace{14mu}{circuit}\mspace{14mu}{current}}} \\{V_{OC} = {{open}\mspace{14mu}{circuit}\mspace{14mu}{voltage}}} \\{{FF} = {{fill}\mspace{14mu}{factor}}} \\{\eta = {{power}\mspace{14mu}{conversion}\mspace{14mu}{efficiency}}}\end{matrix}\quad$

Example D Formulation and Device

The following electrolyte formulations are synthesized to demonstratethe unexpected advantage of electrolyte formulations according to theinvention (emim MHB) together with a list of additives.

The electrolyte formulations are prepared through mixing of1,3-dimethylimidazolium iodide (mmimI), iodine, guanidinium thiocyanate(guaSCN), emim [BH(CN)₃] (emim MHB) with and without additives as listedbelow.

guaI means guanidinium iodide.

TABLE 5 electrolytes 22 to 26 Ingredients Electrolyte in weight % 22 2324 25 26 I₂ 1.5 1.5 1.5 1.4 1.5 mmimI 36.7 35.8 36.0 34.8 35.9 guaSCN0.7 0.7 0.7 0.7 0.7 emim MHB 61.1 59.7 59.9 58.0 59.9 NBB 0.0 0.0 0.02.0 0.0 Benzimidazole 0.0 2.3 0.0 0.0 0.0 guaI 0.0 0.0 2.0 3.0 0.0 emimSCN 0.0 0.0 0.0 0.0 2.0

The dye sensitized solar cells are fabricated and measured as disclosedin example C with Z907, with the dye C106/DINHOP and with the dye D358.

Table 6 summarizes the results of the measurements of the above citedelectrolyte formulations:

Electrolyte J_(SC) [mAcm⁻²] V_(OC) [V] FF η [%] Z907 22 12.05 0.72 0.726.30 23 11.04 0.76 0.72 6.00 24 11.80 0.75 0.70 6.20 25 10.63 0.80 0.746.62 26 11.83 0.76 0.73 6.60 C106 22 13.75 0.68 0.71 6.57 23 12.50 0.710.73 6.53 D358 22 12.18 0.65 0.68 5.36 24 12.75 0.64 0.68 5.62 25 10.730.72 0.72 5.52 26 11.75 0.67 0.70 5.45

Example E Formulation and Device

The following electrolyte formulations are synthesized to demonstratethe unexpected advantage of electrolyte formulations according to theinvention:

The electrolyte formulations are prepared through mixing of1-ethyl-3-methylimidazolium iodide (emimI) or 1,1-dimethylpyrrolidiniumiodide (mmplI), iodine, N-butylbenzimidazole (NBB), guanidiniumthiocyanate (guaSCN) and the corresponding ionic liquid as indicatedsuch as bmpl TCB, bmpl MHB (bmpl=1-butyl-1-methylpyrrolidinium),triethylsulfonium monohydridotricyanoborate (et3S MHB),3-methylpyridinium monohydridotricyanoborate (B3MPYR MHB) and or.

TABLE 7 electrolytes 27 to 32 Ingredients Electrolyte in weight % 27* 2829* 30 31 32 I₂ 1.3 1.3 1.3 1.3 1.3 1.3 emimI 35.0 35.0 0.0 0.0 35.035.0 mmplI 0.00 0.00 35.00 35.00 0.00 0.00 guaSCN 0.7 0.7 0.7 0.7 0.70.7 bmpl TCB 60.0 0.00 60.0 0.00 0.00 0.00 bmpl MHB 0.00 60.0 0.00 60.00.00 0.00 et3S MHB 0.00 0.00 0.00 0.00 60.0 0.00 B3MPYR 0.00 0.00 0.000.00 0.00 60.0 MHB NBB 3.0 3.0 3.0 3.0 3.0 3.0 *not according to theinvention

The dye sensitized solar cells are fabricated and measured as disclosedin example C but with the dye Z907.

Table 8 summarizes the results of the measurements of the above citedelectrolyte formulations:

Electrolyte J_(SC) [mAcm⁻²] V_(OC) [V] FF η [%]  27* 9.27 0.72 0.60 4.0228 11.38 0.74 0.64 5.37  29* 5.42 0.71 0.62 2.38 30 7.37 0.72 0.58 3.1031 11.81 0.71 0.71 5.95 32 11.78 0.69 0.61 4.95 *not according to theinvention

The invention claimed is:
 1. Compounds of formula I[Kt]^(z+) z[BH(CN)₃]⁻  I in which [Kt]^(z+) denotes an inorganic ororganic cation and z is 1, 2, 3 or 4, where sodiumhydrido-tricyano-borate, potassium hydrido-tricyano-borate, silverhydrido-tricyano-borate and PPN[HB(CN)₃] are excluded.
 2. A compoundaccording to claim 1, wherein [Kt]^(z+) is an organic cation selectedfrom the group comprising iodonium, tritylium, sulfonium, oxonium,ammonium, phosphonium, uronium, thiouronium, guanidinium cations orheterocyclic cations.
 3. A compound according to claim 1, in whichKt^(z+) denotes an inorganic cation selected from the group of H⁺, NO⁺,Li⁺, Mg²⁺, Cu⁺, Cu²⁺, Zn²⁺, Ca²⁺, Y⁺³, Yb⁺³, La⁺³, Sc⁺³, Ce⁺³, Nd⁺³,Tb⁺³, Sm⁺³ and complex (ligands containing) metal cations an organiccation, which is a tritylium cation, in which the phenyl groups areoptionally substituted by straight-chain or branched alkyl groups having1 to 20 C atoms, straight-chain or branched alkenyl having 2 to 20 Catoms and one or more double bonds or straight-chain or branched alkynylhaving 2 to 20 C atoms and one or more triple bonds, an oxonium cationof formula (1) or a sulfonium cation of formula (2)[(R^(o))₃O]⁺  (1)[(R^(o))₃S]⁺  (2), where R^(o) each independently of one another denotesa straight-chain or branched alkyl group having 1-8 C atoms,non-substituted phenyl or phenyl which is substituted by R^(1*), OR′,N(R′)₂, CN or halogen and in case of sulfonium cations of formula (2)additionally denotes each independently (R′″)₂N, R′ is independently ofeach other H, non-fluorinated, partially fluorinated or perfluorinatedstraight-chain or branched C₁- to C₁₈-alkyl, saturated C₃- toC₇-cycloalkyl, non-substituted or substituted phenyl, R^(1*) isindependently of each other non-fluorinated, partially fluorinated orperfluorinated straight-chain or branched C₁- to C₁₈-alkyl, saturatedC₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and R′″ isindependently of each other straight-chain or branched C₁ to C₆ alkyl;an ammonium cation of formula (3)[NR₄]⁺  (3), where R in each case, independently of one another, denotesH, OR′, N(R′)₂, with the proviso that a maximum of one R in formula (3)is OR′ or N(R′)₂, straight-chain or branched alkyl having 1-20 C atoms,straight-chain or branched alkenyl having 2-20 C atoms and one or moredouble bonds, straight-chain or branched alkynyl having 2-20 C atoms andone or more triple bonds, saturated, partially or fully unsaturatedcycloalkyl having 3-7 C atoms, which is optionally substituted bystraight-chain or branched alkyl groups having 1-6 C atoms, where one ortwo R may be fully substituted by halogens, and one or more of R areoptionally partially substituted by halogens, and/or by —OH, —OR′, —CN,—N(R′)₂, —C(O)OH, —C(O)OR′, —C(O)R′, —C(O)N(R′)₂, —SO₂N(R′)₂, —C(O)X,—SO₂OH, —SO₂X, —NO₂, —SR′, —S(O)R′, and/or —SO₂R′ and where one or twonon-adjacent carbon atoms in R which are not in the α-position areoptionally replaced by atoms and/or atom groups selected from the groupconsisting of —O—, —S—, —S(O)—, —SO₂—, —SO₂O—, —C(O)—, —C(O)O—,—N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—, —OP(O)R′O—,—P(O)(N(R′)₂)NR′—, —P(R′)₂═N— and —P(O)R′— where R′ each independentlyis H, non-fluorinated, partially fluorinated or perfluorinatedstraight-chain or branched C₁- to C₁₈-alkyl, saturated C₃- toC₇-cycloalkyl, non-substituted or substituted phenyl and X eachindependently is halogen; a phosphonium cation of formula (4)[P(R²)₄]⁺  (4), where R² in each case, independently of one another,denotes H, OR′ or N(R′)₂, straight-chain or branched alkyl having 1-20 Catoms, straight-chain or branched alkenyl having 2-20 C atoms and one ormore double bonds, straight-chain or branched alkynyl having 2-20 Catoms and one or more triple bonds, saturated, partially or fullyunsaturated cycloalkyl having 3-7 C atoms, which is optionallysubstituted by straight-chain or branched alkyl groups having 1-6 Catoms, where one or two R² are optionally fully substituted by halogens,and one or more of R² are optionally partially substituted by halogens,in particular and/or by —OH, —OR′, —CN, —N(R′)₂, —C(O)OH, —C(O)OR′,—C(O)R′, —C(O)N(R′)₂, —SO₂N(R′)₂, —C(O)X, —SO₂OH, —SO₂X, —NO₂, —SR′,—S(O)R′, —SO₂R′ and where one or two non-adjacent carbon atoms in R²which are not in the α-position may be replaced by atoms and/or atomgroups selected from the group consisting of —O—, —S—, —S(O)—, —SO₂—,—SO₂O—, —C(O)—, —C(O)O—, —N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—,—OP(O)R′O—, —P(O)(N(R′)₂)NR′—, —P(R′)₂═N— or —P(O)R′— where R′ eachindependently is H, non-fluorinated, partially fluorinated orperfluorinated straight-chain or branched C₁- to C₁₈-alkyl, saturatedC₃- to C₇-cycloalkyl, non-substituted or substituted phenyl and X eachindependently is halogen; a uronium cation of formula (5)[C(NR³R⁴)(OR⁵)(NR⁶R⁷)]⁺  (5), where R³ to R⁷ each, independently of oneanother, denote H, where H is excluded for R⁵, straight-chain orbranched alkyl having 1 to 20 C atoms, straight-chain or branchedalkenyl having 2-20 C atoms and one or more double bonds, straight-chainor branched alkynyl having 2-20 C atoms and one or more triple bonds,saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms,which is optionally substituted by straight-chain or branched alkylgroups having 1-6 C atoms, where one or two of the substituents R³ to R⁷are optionally fully substituted by halogens, and one or more of R³ toR⁷ are optionally partially substituted by halogens, and/or by —OH,—OR′, —N(R′)₂, —CN, —C(O)OH, —C(O)OR′, —C(O)R′, —C(O)N(R′)₂, —SO₂N(R′)₂,—C(O)X, —SO₂OH, —SO₂X, —SR′, —S(O)R′, —SO₂R′, and/or —NO₂ and where oneor two non-adjacent carbon atoms in R³ to R⁷ which are not in theα-position are optionally replaced by atoms and/or atom groups selectedfrom the group —O—, —S—, —S(O)—, —SO₂—, —SO₂O—, —C(O)—, —C(O)O—,—N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—, —OP(O)R′O—,—P(O)(N(R′)₂)NR′—, —P(R′)₂═N— and —P(O)R′— where R′ each independentlyis H, non-fluorinated, partially fluorinated or perfluorinatedstraight-chain or branched C₁- to C₁₈-alkyl, saturated C₃- toC₇-cycloalkyl, non-substituted or substituted phenyl and X eachindependently is halogen; a thiouronium cation of formula (6)[C(NR³R⁴)(SR⁵)(NR⁶R⁷)]⁺  (6), where R³ to R⁷ each, independently of oneanother, denote H, where H is excluded for R⁵, straight-chain orbranched alkyl having 1 to 20 C atoms, straight-chain or branchedalkenyl having 2-20 C atoms and one or more double bonds, straight-chainor branched alkynyl having 2-20 C atoms and one or more triple bonds,saturated, partially or fully unsaturated cycloalkyl having 3-7 C atoms,which is optionally substituted by straight-chain or branched alkylgroups having 1-6 C atoms, where one or two of R³ to R⁷ are optionallyfully substituted by halogens, and one or more of the substituents R³ toR⁷ are optionally partially substituted by halogens, and/or by —OH,—OR′, —N(R′)₂, —CN, —C(O)OH, —C(O)OR′, —C(O)R′, —C(O)N(R′)₂, —SO₂N(R′)₂,—C(O)X, —SO₂OH, —SO₂X, —SR′, —S(O)R′, —SO₂R′, and/or —NO₂ and where oneor two non-adjacent carbon atoms in R³ to R⁷ which are not in theα-position are optionally replaced by atoms and/or atom groups selectedfrom the group —O—, —S—, —S(O)—, —SO₂—, —SO₂O—, —C(O)—, —C(O)O—,—N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—, —OP(O)R′O—,—P(O)(N(R′)₂)NR′—, —P(R′)₂═N— and —P(O)R′— where R′ each independentlyis H, non-fluorinated, partially fluorinated or perfluorinatedstraight-chain or branched C₁- to C₁₈-alkyl, saturated C₃- toC₇-cycloalkyl, non-substituted or substituted phenyl and X eachindependently is halogen; a guanidinium cation of formula (7)[C(NR⁸R⁹)(NR¹⁰R¹¹)(NR¹²R¹³)]⁺  (7), where R⁸ to R¹³ each, independentlyof one another, denote H, —CN, N(R′)₂, —OR′, straight-chain or branchedalkyl having 1 to 20 C atoms, straight-chain or branched alkenyl having2-20 C atoms and one or more double bonds, straight-chain or branchedalkynyl having 2-20 C atoms and one or more triple bonds, saturated,partially or fully unsaturated cycloalkyl having 3-7 C atoms, which isoptionally substituted by straight-chain or branched alkyl groups having1-6 C atoms, where one or two of the substituents R⁸ to R¹³ areoptionally fully substituted by halogens, and one or more of thesubstituents R⁸ to R¹³ are optionally partially substituted by halogens,and/or by —OH, —OR′, —N(R′)₂, —CN, —C(O)OH, —C(O)OR′, —C(O)R′,—C(O)N(R′)₂, —SO₂N(R′)₂, —C(O)X, —SO₂OH, —SO₂X, —SR′, —S(O)R′, —SO₂R′,and/or —NO₂ and where one or two non-adjacent carbon atoms in R⁸ to R¹³which are not in the α-position are optionally replaced by atoms and/oratom groups selected from the group —O—, —S—, —S(O)—, —SO₂—, —SO₂O—,—C(O)—, —C(O)O—, —N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—, —OP(O)R′O—,—P(O)(N(R′)₂)NR′—, —P(R′)₂═N— and —P(O)R′—, where R′ each independentlyis H, non-fluorinated, partially fluorinated or perfluorinatedstraight-chain or branched C₁- to C₁₈-alkyl, saturated C₃- toC₇-cycloalkyl, non-substituted or substituted phenyl and X eachindependently is halogen; a heterocyclic cation of formula (8)[HetN]^(z+)  (8) which [HetN]^(z+) denotes a heterocyclic cationselected from the group consisting of

where R¹′ to R⁴′ each, independently of one another, denote H,straight-chain or branched alkyl having 1-20 C atoms, straight-chain orbranched alkenyl having 2-20 C atoms and one or more double bonds,straight-chain or branched alkynyl having 2-20 C atoms and one or moretriple bonds, saturated, partially or fully unsaturated cycloalkylhaving 3-7 C atoms, which is optionally substituted by straight-chain orbranched alkyl groups having 1-6 C atoms, saturated, partially or fullyunsaturated heteroaryl, heteroaryl-C₁-C₆-alkyl or aryl-C₁-C₆-alkyl andR^(2′) denote additionally F, Cl, Br, I, —CN, —OR′, —N(R′)₂, —P(O)(R′)₂,—P(O)(OR′)₂, —P(O)(N(R′)₂)₂, —C(O)R′, —C(O)OR′, —C(O)X, —C(O)N(R′)₂,—SO₂N(R′)₂, —SO₂OH, —SO₂X, —SR′, —S(O)R′, —SO₂R′ and/or NO₂, with theproviso that R¹′, R³′, R⁴′ are in this case independently of each otherH and/or a straight-chain or branched alkyl having 1-20 C atoms, and/ora straight-chain or branched alkenyl having 2-20 C atoms and one or moredouble bonds, where the substituents R^(1′), R^(2′), R^(3′) and/orR^(4′) together optionally form a ring system, where one to threesubstituents R^(1′) to R^(4′) are optionally fully substituted byhalogens, and one or more of R^(1′) to R^(4′) are optionally partiallysubstituted by halogens, and/or by —OH, —OR′, N(R′)₂, —CN, —C(O)OH,—C(O)OR′, —C(O)R′, —C(O)N(R′)₂, —SO₂N(R′)₂, —C(O)X, —SO₂OH, —SO₂X, —SR′,—S(O)R′, —SO₂R′, and/or —NO₂, but where R^(1′) and R^(4′) cannotsimultaneously be fully substituted by halogens and where, in thesubstituents R^(1′) to R^(4′), one or two non-adjacent carbon atomswhich are not bonded to the heteroatom are optionally replaced by atomsand/or atom groups selected from the —O—, —S—, —S(O)—, —SO₂—, —SO₂O—,—C(O)—, —C(O)O—, —N⁺(R′)₂—, —P(O)R′O—, —C(O)NR′—, —SO₂NR′—, —OP(O)R′O—,—P(O)(N(R′)₂)NR′—, —P(R′)₂═N— or —P(O)R′—, where R′ each independentlyis H, non-fluorinated, partially fluorinated or perfluorinatedstraight-chain or branched C₁- to C₁₈-alkyl, saturated C₃- toC₇-cycloalkyl, non-substituted or substituted phenyl and X eachindependently is halogen or a iodonium cation of formula (9)

where the aryl group Ar denotes each independently of each other arylwith 6 to 30 C atoms which is non-substituted or substituted with atleast a straight-chain or branched alkyl group having 1 to 20 C atoms, astraight-chain or branched alkenyl group having 2 to 20 C atoms and oneor more double bonds, a straight-chain or branched alkynyl group having2 to 20 C atoms and one or more triple bonds, R^(1*), NO₂, SR′^(′),N(R′)₂, CN and/or halogen, where R′ each independently is H,non-fluorinated, partially fluorinated or perfluorinated straight-chainor branched C₁- to C₁₈-alkyl, saturated C₃- to C₇-cycloalkyl,non-substituted or substituted phenyl, where R^(1*) each independentlyis non-fluorinated, partially fluorinated or Perfluorinatedstraight-chain or branched C₁- to C₁₈-alkyl, saturated C₃- toC₇-cycloalkyl, non-substituted or substituted phenyl, and halogen is F,Cl, Br or I.
 4. A process for preparing a compound of formula Iaccording to claim 1 in which [Kt]^(z+) is another cation than thealkali metal cation in the starting material and z denotes 1, 2, 3 or 4in a salt-exchange reaction, comprising reacting an alkali metal salt offormula I-1[Me]⁺[BH(CN)₃]⁻  I-1 in which [Me]⁺ is an alkali metal cation orreactingH[BH(CN)₃] with a compound of formula VKtA  V, in which Kt has a meaning of an organic cation or inorganiccation other than the alkali metal cation of the compound of formula I-1or H⁺ and A denotes F⁻, Cl⁻, Br⁻, I⁻, OH⁻, [HF₂]⁻, [CN]⁻, [SCN]⁻,[R₁COO]⁻, [R₁OC(O)O]⁻, [R₁SO₃]⁻, [R₂COO]⁻, [R₂SO₃]⁻, [R₁OSO₃]⁻, [PF₆]⁻,[BF₄]⁻, [SO₄]²⁻, [HSO₄]¹⁻, [NO₃]⁻, [(R₂)₂P(O)O]⁻, [R₂P(O)O₂]²⁻,[(R₁O)₂P(O)O]⁻, [(R₁O)P(O)O₂]²⁻, [(R₁O)R₁P(O)O]⁻, tosylate, malonatewhich is optionally substituted by straight-chain or branched alkylgroups having 1 to 4 C atoms, [HOCO₂]⁻ or [CO₃]²⁻, with the proviso that[SO₄]²⁻ and [CO₃]²⁻ are only for the synthesis of compounds of formula Ihaving another metal cation than the alkali metal cation of the compoundof formula I-1, R₁ is each independently of another a straight-chain orbranched alkyl group having 1 to 12 C atoms and R₂ is each independentlyof one another a straight-chain or branched perfluorinated alkyl grouphaving 1 to 12 C atoms.
 5. An electrolyte formulation comprising atleast one compound of formula I according to claim
 1. 6. Anelectrochemical and/or optoelectronic device comprising an electrolyteformulation according to claim
 5. 7. A method for cationicpolymerization or photo polymerization or for photo acid generative,comprising initiating said cationic polymerization or photopolymerization, or generating said photo acid by a compound of formula Iaccording to claim 3 in which [Kt]^(z+) is a cation of formula (2), (5),(6), (9), tritylium, pyrylium, 1-benzopyrylium or 2-benzopyrylium whichacts as a cationic polymerization initiator, photo-polymerizationinitiator or photo-acid generator.
 8. A media for a chemical reaction, acatalyst and/or a media in a catalytical process, a conducting salt, acomponent of electrolytes for the application in electrochemical cells,a component of supporting electrolytes for an electrochemical process, asurfactant, a phase-transfer catalyst, a trainer, an extractant; anantistatic additive, a plasticiser; a heat-transfer-medium, a modifierfor a membrane or textile material; a lubricant, an additive to alubricant composition or to an engineering fluid; a hydraulic fluid oran additive to a hydraulic fluid, comprising a compound of formula Iaccording to claim 1 in which [Kt]^(z+) is an organic cation or H⁺ and zis 1, 2, 3 or
 4. 9. A compound according to claim 1, in which Kt^(z+)denotes an inorganic cation selected from the group consisting of H⁺,NO⁺,Li⁺, Mg²⁺, Cu⁺, Cu²⁺, Zn²⁺, Ca²⁺, Y⁺³, Yb⁺³, La⁺³, Sc⁺³, Ce⁺³, Nd⁺³,Tb⁺³, Sm⁺³ and xomplex (ligands containing) metal cations, wherein themetal is selected from the group consisting of rare-earths, transitionsmetals and noble metals.
 10. A compound according to claim 1, in whichKt^(z+) denotes an inorganic cation selected from the group consistingof H⁺, NO⁺, Li⁺, Mg ²⁺, Cu⁺, Cu²⁺, Zn²⁺, Ca²⁺, Y⁺³, Yb⁺³, La⁺³, Sc⁺³,Ce⁺³, Nd⁺³, Tb⁺³, Sm⁺³ and complex (ligands containing) metal cations,wherein the metal is selected from the group consisting of rhodium,ruthenium, iridium, palladium, platinum, osmium, cobalt, nickel, iron,chromium, molybdenum, tungsten, vanadium, titanium, zirconium, hafnium,thorium, uranium and gold.
 11. A compound according to claim 3, in whichKt^(z+) denotes a heterocyclic cation of formula (8)[HetN]^(z+)   (8) which [HetN]^(z+) denotes a heterocyclic cationselected from the group consisting of


12. A compound according to claim 3, in which Kt^(z+) denotes aheterocyclic cation of formula (8)[HetN]^(z+)   (8) which [HetN]^(z+) denotes a heterocyclic cationselected from the group consisting of


13. A compound according to claim
 3. in which Kt^(z+) denotes aheterocyclic cation of formula (8)[HetN]^(z+)   (8) which [HetN]^(z+) denotes a heterocyclic cationselected from the group consisting of


14. A compound according to claim 3, in which Kt^(z+) denotes aheterocyclic cation of formula (8)[HetN]^(z+)   (8) which [HetN]^(z+) denotes a heterocyclic cationselected from the group consisting of